ci: allow opt-out of changelog lint for internal changes

We introduced a lint in #4620 that ensures the changelog is updated when we touch a certain crate. This however leads to many "false-positives" where a change to the source code is not actually worth mentioning in the changelog.

To opt out of this change, this patch adds a condition to the job that checks for a `internal:$crate` label and if that is applied, it doesn't run the lint.

Pull-Request: #4673.

.github/workflows/ci.yml

@@ -78,7 +78,8 @@ jobs:
           !startsWith(github.event.pull_request.title, 'chore') &&
           !startsWith(github.event.pull_request.title, 'refactor') &&
           !startsWith(github.event.pull_request.title, 'deps') &&
-          !startsWith(github.event.pull_request.title, 'docs')
+          !startsWith(github.event.pull_request.title, 'docs') &&
+          !contains(github.event.pull_request.labels.*.name, 'internal-change')
         run: |
           git fetch origin master:master
           ./scripts/ensure-version-bump-and-changelog.sh

docs/maintainer-handbook.md

@@ -26,6 +26,14 @@ Once a PR fulfills all merge requirements (approvals, passing CI, etc), applying
 In case of a trivial code change, maintainers may choose to apply the `trivial` label.
 This will have mergify approve your PR, thus fulfilling all requirements to automatically queue a PR for merging.
 
+## Changelog entries
+
+Our CI checks that each crate which is modified gets a changelog entry.
+Whilst this is a good default safety-wise, it creates a lot of false-positives for changes that are internal and don't need a changelog entry.
+
+For PRs that in the categories `chore`, `deps`, `refactor` and `docs`, this check is disabled automatically.
+Any other PR needs to explicitly disable this check if desired by applying the `internal-change` label.
+
 ## Dependencies
 
 We version our `Cargo.lock` file for better visibility into which dependencies are required for a functional build.