ci: fix closed quote (#34)

Author: jef

.github/workflows/nightly-release.yaml

@@ -37,4 +37,4 @@ jobs:
         if: steps.code-change.outputs.should-run == 'true'
         run: |
           docker push "ghcr.io/${GITHUB_REPOSITORY}:${GITHUB_SHA:0:7}"
-          docker push "ghcr.io/${GITHUB_REPOSITORY}:nightly
+          docker push "ghcr.io/${GITHUB_REPOSITORY}:nightly"