added new workflow for releasing the mq-exporter container image

.github/workflows/mq-exporter-build.yaml

@@ -0,0 +1,45 @@
+name: Build/Release IBM MQ Exporter
+
+# on:
+#   push:
+#     branches:
+#       - main
+#     paths:
+#       - "container/**"
+#       - ".github/workflows/container.yaml"
+
+jobs:
+  push-images:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        app:
+          - "mq-metric-samples"
+    steps:
+      - name: Get Tag From Environment
+        id: get-tag
+        run: printf '::set-output name=tag::%s' "$(git rev-parse --short HEAD)"
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Login to Github Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          context: submodules/${{ matrix.app }}
+          file: submodules/${{ matrix.app }}/Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push:  true
+          tags:  ghcr.io/observiq/${{ matrix.app }}:${{ steps.get-tag.outputs.tag }}