[feat] Uploading mm-te-test artifacts to mattermost docker registry

Required by Cloud Platform team for smooth migration of Spinwick service to the new DockerHub registry.
Context: https://community.mattermost.com/private-core/pl/3jzzxzfiji8hx833ewyuthzkjh

.github/workflows/artifacts.yml

@@ -66,6 +66,40 @@ jobs:
         export DOCKER_CLI_EXPERIMENTAL=enabled
         export MM_PACKAGE=https://pr-builds.mattermost.com/$REPO_NAME/commit/${{ github.sha }}/mattermost-team-linux-amd64.tar.gz
         docker buildx build --push --build-arg MM_PACKAGE=$MM_PACKAGE -t mattermostdevelopment/mm-te-test:${TAG} .
+  # Temporary uploading also to mattermost/mm-te-test:${TAG} except mattermostdevelopment/mm-te-test:${TAG}
+  # Context: https://community.mattermost.com/private-core/pl/3jzzxzfiji8hx833ewyuthzkjh
+  build-docker-temp:
+    name: cd/Build and push docker image
+    needs: upload-s3
+    env:
+      REPO_NAME: ${{ github.event.repository.name }}
+    runs-on: ubuntu-22.04
+    if: >
+      github.event.workflow_run.event == 'pull_request' &&
+      github.event.workflow_run.conclusion == 'success'
+    steps:
+    - name: cd/Login to Docker Hub
+      uses: docker/login-action@3da7dc6e2b31f99ef2cb9fb4c50fb0971e0d0139 # v2.1.0
+      with:
+        username: ${{ secrets.DOCKERHUB_USERNAME }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+    - name: cd/Download artifacts
+      uses: dawidd6/action-download-artifact@0c49384d39ceb023b8040f480a25596fd6cf441b # v2.26.0
+      with:
+        workflow_conclusion: success
+        name: server-build-artifact
+        path: server/build/
+    - name: cd/Setup Docker Buildx
+      uses: docker/setup-buildx-action@11e8a2e2910826a92412015c515187a2d6750279 # v2.4
+    - name: cd/Docker build and push
+      env:
+        DOCKER_CLI_EXPERIMENTAL: enabled
+      run: |
+        export TAG=$(echo "${{ github.event.pull_request.head.sha || github.sha }}" | cut -c1-7)
+        cd server/build
+        export DOCKER_CLI_EXPERIMENTAL=enabled
+        export MM_PACKAGE=https://pr-builds.mattermost.com/$REPO_NAME/commit/${{ github.sha }}/mattermost-team-linux-amd64.tar.gz
+        docker buildx build --push --build-arg MM_PACKAGE=$MM_PACKAGE -t mattermost/mm-te-test:${TAG} .
   sentry:
     name: Send build info to sentry
     if: >