CI: build container when the version is a clean git tag 15

.forgejo/workflows/build.yaml

@@ -23,7 +23,7 @@ jobs:
       - name: Check if the container should be built
         id: builder
         env:
-          RUN: toJSON(${{ inputs.build || !contains(steps.version.outputs.version, '-')) }}
+          RUN: ${{ toJSON(inputs.build || !contains(steps.version.outputs.version, '-')) }}
         run: |
           echo "run=$RUN" >> $GITHUB_OUTPUT
           echo "Run build: $RUN"