ci: fix GitHub Actions expression syntax in release-on-main workflow

The dry-run summary step used double quotes ("") in the if-expression,
which GitHub Actions expression parser does not support. Replace with
single quotes to match all other conditions in the workflow.

Validated with yaml-lint and actionlint (no errors, only shellcheck style hints).

Author: benvinegar

.github/workflows/release-on-main.yml

@@ -268,7 +268,7 @@ jobs:
           echo "Reason: ${{ steps.decide.outputs.reason }}" >> "$GITHUB_STEP_SUMMARY"
 
       - name: Dry-run release summary
-        if: steps.bump.outputs.tag != "" && steps.dryrun.outputs.enabled == "true"
+        if: steps.bump.outputs.tag != '' && steps.dryrun.outputs.enabled == 'true'
         run: |
           echo "## Dry run: no release published" >> "$GITHUB_STEP_SUMMARY"
           echo "Decision: ${{ steps.decide.outputs.decision }}" >> "$GITHUB_STEP_SUMMARY"