Build the docker file always to check that it can be deployed.

Author: sydseter

.github/workflows/copi-build.yml

@@ -29,6 +29,8 @@
         - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
           with:
             ref: ${{ github.event.pull_request.head.sha }}
+        - name: build project
+          run: docker build -f ./Dockerfile .
         - name: Cache deps
           id: cache-deps
           uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3