github: Docker public image build doesn't depend on coverage

Today, the step to build the Docker public image depends on the coverage
run. This dependency isn't necessary, as the coverage could be failing
for a variety of reasons (e.g. codecov being down) and doesn't signal
any problem with chasquid itself.

So this patch fixes that: if the integration tests pass, then that is
good enough for building the public image.

.github/workflows/docker.yml

@@ -57,7 +57,7 @@ jobs:
   public-image:
     runs-on: ubuntu-latest
     timeout-minutes: 15
-    needs: [integration, coverage]
+    needs: [integration]
     if: github.event_name == 'push'
     steps:
       - uses: actions/checkout@v4