fix: correct expression quoting in release.yml containers list (#1936)

The needs[] bracket expressions used doubled single quotes
(needs[''build-squid'']) inside a YAML literal block (|). In a
literal block there is no YAML quote escaping, so the doubled
quotes were passed verbatim to the expression evaluator, causing:

  Unexpected symbol: 'build-squid''' at position 9

Fix by switching the shell strings from single to double quotes,
allowing single quotes inside ${{ }} expressions to work correctly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: lpcox

.github/workflows/release.yml

@@ -511,11 +511,11 @@ jobs:
         run: |
           mkdir -p release
           printf '%s\n' \
-            'ghcr.io/${{ github.repository }}/squid@${{ needs[''build-squid''].outputs.digest }}' \
-            'ghcr.io/${{ github.repository }}/agent@${{ needs[''build-agent''].outputs.digest }}' \
-            'ghcr.io/${{ github.repository }}/agent-act@${{ needs[''build-agent-act''].outputs.digest }}' \
-            'ghcr.io/${{ github.repository }}/api-proxy@${{ needs[''build-api-proxy''].outputs.digest }}' \
-            'ghcr.io/${{ github.repository }}/cli-proxy@${{ needs[''build-cli-proxy''].outputs.digest }}' \
+            "ghcr.io/${{ github.repository }}/squid@${{ needs['build-squid'].outputs.digest }}" \
+            "ghcr.io/${{ github.repository }}/agent@${{ needs['build-agent'].outputs.digest }}" \
+            "ghcr.io/${{ github.repository }}/agent-act@${{ needs['build-agent-act'].outputs.digest }}" \
+            "ghcr.io/${{ github.repository }}/api-proxy@${{ needs['build-api-proxy'].outputs.digest }}" \
+            "ghcr.io/${{ github.repository }}/cli-proxy@${{ needs['build-cli-proxy'].outputs.digest }}" \
             > release/containers.txt
           echo "Generated containers.txt:"
           cat release/containers.txt