fix(ghcr-prune): actually delete on scheduled runs

The dry-run expression evaluated to true for every non-dispatch event,
so the weekly schedule never deleted anything despite 628eb65 taking the
prune live (17724 versions pending as of run 39580413008). Scheduled
runs now delete; manual dispatch still honors the dry-run input.

Author: KingPin

.github/workflows/ghcr-prune.yml

@@ -34,4 +34,4 @@ jobs:
           package: php-docker
           delete-untagged: true
           older-than: 28 days
-          dry-run: ${{ github.event_name != 'workflow_dispatch' || inputs.dry-run }}
+          dry-run: ${{ github.event_name == 'workflow_dispatch' && inputs.dry-run }}