ci: enhance build process (#2755)

This new script is a clean way of handling the installation of packages.
I think the huge `RUN` command in `Dockerfile` was hard to read and
maintain.

Using a script is a non-issue, as the image is rebuilt whenever the
script is touched.

Co-authored-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>

.github/workflows/generic_publish.yml

@@ -72,7 +72,7 @@ jobs:
         run: echo "::set-output name=version::$(<VERSION)"
 
       - name: 'Build and publish images'
-        uses: docker/build-push-action@v3.1
+        uses: docker/build-push-action@v3.1.1
         with:
           context: .
           build-args: |