Add gh workflow for pushing to dockerhub

Author: kheal

.github/workflows/dockerhub_push.yml

@@ -0,0 +1,21 @@
+name: 
+
+on:
+  workflow_dispatch:
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+    
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Build and push Docker image
+        run: make docker-nmdc
+