Improve no-important-files-changed workflow (#345)

- Fix permission error when trying to create the comment
- Use reusable workflow to allow for easier updating
- Ignore .approaches and .articles directories
- Ignore .docs and .meta directories entirely

tracks-files/.github/workflows/no-important-files-changed.yml

@@ -1,68 +1,23 @@
 name: No important files changed
 
 on:
-  pull_request:
+  pull_request_target:
     types: [opened]
     branches: [main]
+    paths:
+      - "exercises/concept/**"
+      - "exercises/practice/**"
+      - "!exercises/*/*/.approaches/**"
+      - "!exercises/*/*/.articles/**"
+      - "!exercises/*/*/.docs/**"
+      - "!exercises/*/*/.meta/**"
 
 permissions:
   pull-requests: write
 
 jobs:
-  no_important_files_changed:
-    name: No important files changed
-    runs-on: ubuntu-22.04
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
-
-      - name: Check if important files changed
-        id: check
-        run: |
-          set -exo pipefail
-
-          # fetch a ref to the main branch so we can diff against it
-          git remote set-branches origin main
-          git fetch --depth 1 origin main
-
-          for changed_file in $(git diff --diff-filter=M --name-only origin/main); do
-            if ! echo "$changed_file" | grep --quiet --extended-regexp 'exercises/(practice|concept)' ; then
-              continue
-            fi
-            slug="$(echo "$changed_file" | sed --regexp-extended 's#exercises/[^/]+/([^/]+)/.*#\1#' )"
-            path_before_slug="$(echo "$changed_file" | sed --regexp-extended "s#(.*)/$slug/.*#\\1#" )"
-            path_after_slug="$( echo "$changed_file" | sed --regexp-extended "s#.*/$slug/(.*)#\\1#" )"
-
-            if ! [ -f "$path_before_slug/$slug/.meta/config.json" ]; then
-              # cannot determine if important files changed without .meta/config.json
-              continue
-            fi
-
-            #  returns 0 if the filter matches, 1 otherwise
-            #  | contains($path_after_slug)
-            if jq --exit-status \
-              --arg path_after_slug "$path_after_slug" \
-              '[.files.test, .files.invalidator, .files.editor] | flatten | index($path_after_slug)' \
-              "$path_before_slug/$slug/.meta/config.json" \
-              > /dev/null;
-            then
-              echo "important_files_changed=true" >> "$GITHUB_OUTPUT"
-              exit 0
-            fi
-          done
-
-          echo "important_files_changed=false" >> "$GITHUB_OUTPUT"
-
-      - name: Suggest to add [no important files changed]
-        if: steps.check.outputs.important_files_changed == 'true'
-        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea
-        with:
-          github-token: ${{ github.token }}
-          script: |
-            const body = "This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.\n\nIf this PR does **not** affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), **please add the following to the merge-commit message** which will stops student's tests from re-running. Please copy-paste to avoid typos.\n```\n[no important files changed]\n```\n\n For more information, refer to the [documentation](https://exercism.org/docs/building/tracks#h-avoiding-triggering-unnecessary-test-runs). If you are unsure whether to add the message or not, please ping `@exercism/maintainers-admin` in a comment. Thank you!"
-            github.rest.issues.createComment({
-              issue_number: context.issue.number,
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              body: body
-            })
+  pause:
+    uses: exercism/github-actions/.github/workflows/check-no-important-files-changed.yml@main
+    with:
+      repository: ${{ github.event.pull_request.head.repo.owner.login }}/${{ github.event.pull_request.head.repo.name }}
+      ref: ${{ github.head_ref }}