Build push :latest Docker on pushes to main.

.github/workflows/docker_deployment.yml

@@ -1,6 +1,9 @@
 name: Build and deploy Docker image
 
 on:
+  push:
+    branches:
+      - 'dev'
   release:
     types: [created]
   pull_request:
@@ -27,7 +30,7 @@ jobs:
         uses: docker/setup-buildx-action@v2
       -
         name: Login to DockerHub
-        if: github.event_name == 'release'
+        if: github.event_name == 'release' || github.ref == 'refs/heads/main'
         uses: docker/login-action@v2
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
@@ -42,6 +45,16 @@ jobs:
           tags: molpopgen/fwdpy11:latest, molpopgen/fwdpy11:${{ github.event.release.tag_name }}
           file: deployment/docker/Dockerfile
           context: .
+      -
+        name: Build and push from main
+        if: github.ref == 'refs/heads/main'
+        id: docker_bfild_main
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: molpopgen/fwdpy11:latest
+          file: deployment/docker/Dockerfile
+          context: .
       -
         name: Build image
         if: github.event_name == 'pull_request'