ci: Fix posting coverage comments

Author: kjarosh

.github/workflows/test_rust.yml

@@ -10,6 +10,9 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+permissions:
+  pull-requests: write
+
 env:
   FEATURES: lzma,jpegxr
   TEST_OPTS: --workspace --locked --no-fail-fast -j 4
@@ -271,13 +274,23 @@ jobs:
         if: always()
         run: cat target/diff-cover/report.md >> $GITHUB_STEP_SUMMARY
 
-      - name: Comment
+      - name: Generate comment
+        id: generate_comment
         if: always()
         env:
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
         run: |
-          $COVERAGE_SCRIPT comment_report "target/diff-cover/report.json" "${{ github.event.pull_request.number }}" "${RUN_URL}"
+          comment=$($COVERAGE_SCRIPT comment_report "target/diff-cover/report.json" "" "${RUN_URL}")
+          echo "comment<<EOF" >> $GITHUB_OUTPUT
+          echo "$comment" >> $GITHUB_OUTPUT
+          echo "EOF" >> $GITHUB_OUTPUT
+
+      - name: Post comment
+        if: always() && steps.generate_comment.outputs.comment != ''
+        uses: thollander/actions-comment-pull-request@v3
+        with:
+          message: ${{ steps.generate_comment.outputs.comment }}
+          comment-tag: coverage-report
 
   dependencies:
     needs: changes