[CI] Introduce GitHub checks based linting with reviewdog (#900)

* [CI] Introduce linting for branch commits with reviewdog
This utilises the GitHub checks API and could be a potential candidate instead of in-line PR reviews.

* [CI] Change reporter to `github-check`

* [CI] Adjust linting in-line PR commentary to execute with linting step

.buildkite/hooks/post-command

@@ -3,8 +3,8 @@
 set +u
 
 if [[ $BUILDKITE_PULL_REQUEST != "false" ]]; then
-  if [[ $BUILDKITE_LABEL == ":hammer_and_wrench: Unit Test" ]]; then
-    echo "--- :go::service_dog: Linting pull request"
+  if [[ $BUILDKITE_LABEL == ":service_dog: Linting" ]]; then
+    echo "--- :go::service_dog: Provide in-line commentary for pull request"
     reviewdog -reporter=github-pr-review
   fi
 fi

.buildkite/pipeline.sh

@@ -26,6 +26,10 @@ env:
   CI_BYPASS: ${CI_BYPASS}
 
 steps:
+  - label: ":service_dog: Linting"
+    command: "reviewdog -reporter=github-check"
+    if: build.branch !~ /^(master)|(v[0-9]+\.[0-9]+\.[0-9]+)$\$/ && build.env("CI_BYPASS") != "true"
+
   - label: ":hammer_and_wrench: Unit Test"
     command: "authelia-scripts --log-level debug ci"
     if: build.branch !~ /^(master)|(v[0-9]+\.[0-9]+\.[0-9]+)$\$/ && build.env("CI_BYPASS") != "true"