Fix a case with empty secret CI/CD variables

Gemfile

@@ -62,7 +62,7 @@ gem 'akismet', '~> 2.0'
 # Two-factor authentication
 gem 'devise-two-factor', '~> 3.0.0'
 gem 'rqrcode-rails3', '~> 0.1.7'
-gem 'attr_encrypted', '~> 3.0.0'
+gem 'attr_encrypted', '~> 3.1.0'
 gem 'u2f', '~> 0.2.1'
 
 # GitLab Pages

Gemfile.lock

@@ -66,7 +66,7 @@ GEM
       unf
     ast (2.4.0)
     atomic (1.1.99)
-    attr_encrypted (3.0.3)
+    attr_encrypted (3.1.0)
       encryptor (~> 3.0.0)
     attr_required (1.0.0)
     autoprefixer-rails (6.2.3)
@@ -1004,7 +1004,7 @@ DEPENDENCIES
   asciidoctor (~> 1.5.6)
   asciidoctor-plantuml (= 0.0.8)
   asset_sync (~> 2.2.0)
-  attr_encrypted (~> 3.0.0)
+  attr_encrypted (~> 3.1.0)
   awesome_print (~> 1.2.0)
   babosa (~> 1.0.2)
   base32 (~> 0.3.0)