Fix obsoleted URI.{encode,decode} calls for Ruby 2.7

Attempting to use these calls results in these obsolete warnings:

```
warning: URI.escape is obsolete
```

As mentioned by the Knapsack Pro blog:


> The trouble with a concept of “escaping the URI” is that URI consists of
> many components (like path or query), and we don’t want to escape them
> in the same way. For example, it’s fine for a # character to appear at
> the end of the URI (when it’s used as what’s usually called an anchor,
> or in URI parlance - a fragment component) - but when the same # is part
> of user’s input (like in a search query), we want to encode it to ensure
> correct interpretation. Similarly, if the query string value contains
> other reserved characters, like = or &, we do want to escape them so
> that they are not incorrectly interpreted as delimiters, as if they were
> used as reserved characters.
>
> URI.escape relies on a simple gsub operation for the whole string and
> doesn’t differentiate between distinct components, which doesn’t take
> into account intricacies like those mentioned above.


CGI.escape and CGI.encode_www_form_component are often mentioned as
replacements, but both substitute spaces for `+` instead of `%20`. This
doesn't work for Grafana. Using `%20` for spaces everywhere is valid,
which is what `Addressable::URI` does.

.rubocop_todo.yml

@@ -105,14 +105,6 @@ Lint/StructNewOverride:
     - 'app/serializers/environment_serializer.rb'
     - 'lib/gitlab/ci/pipeline/duration.rb'
 
-# Offense count: 7
-Lint/UriEscapeUnescape:
-  Exclude:
-    - 'app/controllers/application_controller.rb'
-    - 'app/models/project_services/drone_ci_service.rb'
-    - 'spec/lib/google_api/auth_spec.rb'
-    - 'spec/requests/api/files_spec.rb'
-
 # Offense count: 65
 # Cop supports --auto-correct.
 Migration/DepartmentName:

app/controllers/application_controller.rb

@@ -484,7 +484,7 @@ class ApplicationController < ActionController::Base
 
   def set_page_title_header
     # Per https://tools.ietf.org/html/rfc5987, headers need to be ISO-8859-1, not UTF-8
-    response.headers['Page-Title'] = URI.escape(page_title('GitLab'))
+    response.headers['Page-Title'] = Addressable::URI.encode_component(page_title('GitLab'))
   end
 
   def set_current_admin(&block)

app/models/project_services/drone_ci_service.rb

@@ -42,7 +42,7 @@ class DroneCiService < CiService
   def commit_status_path(sha, ref)
     Gitlab::Utils.append_path(
       drone_url,
-      "gitlab/#{project.full_path}/commits/#{sha}?branch=#{URI.encode(ref.to_s)}&access_token=#{token}")
+      "gitlab/#{project.full_path}/commits/#{sha}?branch=#{Addressable::URI.encode_component(ref.to_s)}&access_token=#{token}")
   end
 
   def commit_status(sha, ref)
@@ -75,7 +75,7 @@ class DroneCiService < CiService
   def build_page(sha, ref)
     Gitlab::Utils.append_path(
       drone_url,
-      "gitlab/#{project.full_path}/redirect/commits/#{sha}?branch=#{URI.encode(ref.to_s)}")
+      "gitlab/#{project.full_path}/redirect/commits/#{sha}?branch=#{Addressable::URI.encode_component(ref.to_s)}")
   end
 
   def title

lib/grafana/client.rb

@@ -19,8 +19,8 @@ module Grafana
     # @param name [String] Unique identifier for a Grafana datasource
     def get_datasource(name:)
       # CGI#escape formats strings such that the Grafana endpoint
-      # will not recognize the dashboard name. Preferring URI#escape.
-      http_get("#{@api_url}/api/datasources/name/#{URI.escape(name)}") # rubocop:disable Lint/UriEscapeUnescape
+      # will not recognize the dashboard name. Prefer Addressable::URI#encode_component.
+      http_get("#{@api_url}/api/datasources/name/#{Addressable::URI.encode_component(name)}")
     end
 
     # @param datasource_id [String] Grafana ID for the datasource

spec/lib/google_api/auth_spec.rb

@@ -12,12 +12,12 @@ RSpec.describe GoogleApi::Auth do
   end
 
   describe '#authorize_url' do
-    subject { client.authorize_url }
+    subject { Addressable::URI.parse(client.authorize_url) }
 
     it 'returns authorize_url' do
-      is_expected.to start_with('https://accounts.google.com/o/oauth2')
-      is_expected.to include(URI.encode(redirect_uri, URI::PATTERN::RESERVED))
-      is_expected.to include(URI.encode(redirect_to, URI::PATTERN::RESERVED))
+      expect(subject.to_s).to start_with('https://accounts.google.com/o/oauth2')
+      expect(subject.query_values['state']).to eq(redirect_to)
+      expect(subject.query_values['redirect_uri']).to eq(redirect_uri)
     end
   end
 

spec/requests/api/files_spec.rb

@@ -750,7 +750,7 @@ RSpec.describe API::Files do
 
     it "updates existing file in project repo with accepts correct last commit id" do
       last_commit = Gitlab::Git::Commit
-                        .last_for_path(project.repository, 'master', URI.unescape(file_path))
+                        .last_for_path(project.repository, 'master', Addressable::URI.unencode_component(file_path))
       params_with_correct_id = params.merge(last_commit_id: last_commit.id)
 
       put api(route(file_path), user), params: params_with_correct_id
@@ -760,7 +760,7 @@ RSpec.describe API::Files do
 
     it "returns 400 when file path is invalid" do
       last_commit = Gitlab::Git::Commit
-                        .last_for_path(project.repository, 'master', URI.unescape(file_path))
+                        .last_for_path(project.repository, 'master', Addressable::URI.unencode_component(file_path))
       params_with_correct_id = params.merge(last_commit_id: last_commit.id)
 
       put api(route(rouge_file_path), user), params: params_with_correct_id
@@ -772,7 +772,7 @@ RSpec.describe API::Files do
     it_behaves_like 'when path is absolute' do
       let(:last_commit) do
         Gitlab::Git::Commit
-        .last_for_path(project.repository, 'master', URI.unescape(file_path))
+        .last_for_path(project.repository, 'master', Addressable::URI.unencode_component(file_path))
       end
 
       let(:params_with_correct_id) { params.merge(last_commit_id: last_commit.id) }