Do not allow failures in golang guide linting job

Instead of allowing the job to fail, we should configure
golangci-lint to exit 0 on the detection of an issue.

This will allow linting errors to be optionally evaluated
via the codeclimate report in the MR UI, while more serious
problems, such as panics, will be reported.

doc/development/go_guide/index.md

@@ -108,13 +108,13 @@ lint:
     - '[ -e .golangci.yml ] || cp /golangci/.golangci.yml .'
     # Write the code coverage report to gl-code-quality-report.json
     # and print linting issues to stdout in the format: path/to/file:line description
-    - golangci-lint run --out-format code-climate | tee gl-code-quality-report.json | jq -r '.[] | "\(.location.path):\(.location.lines.begin) \(.description)"'
+    # remove `--issues-exit-code 0` or set to non-zero to fail the job if linting issues are detected
+    - golangci-lint run --issues-exit-code 0 --out-format code-climate | tee gl-code-quality-report.json | jq -r '.[] | "\(.location.path):\(.location.lines.begin) \(.description)"'
   artifacts:
     reports:
       codequality: gl-code-quality-report.json
     paths:
       - gl-code-quality-report.json
-  allow_failure: true
 ```
 
 Including a `.golangci.yml` in the root directory of the project allows for