[docker] Build and push docker images to dockerhub. (#2941)

* [docker] Build and push docker images to dockerhub.
Rebuild on changes in the docker directory, and every month.

* change scheduled date, to test faster.

.github/workflows/docker.yml

@@ -0,0 +1,36 @@
+name: Docker update
+
+on:
+    push:
+        branches:
+        - 'master'
+        paths:
+        - 'docker/**'
+    schedule:
+        - cron: '0 3 27 * *'  # build the 27 of each month (for no particular reasons)
+
+jobs:
+  build_docker_image:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    
+    - name: Build docker images
+      run: make -C docker build
+    
+    - name: Log in to Docker Hub
+      uses: docker/login-action@v2
+      with:
+        username: ${{ secrets.DOCKER_USERNAME }}
+        password: ${{ secrets.DOCKER_PASSWORD }}
+    
+    - name: Docker Push dep
+      run: docker push paparazziuav/pprz-dep
+      
+    - name: Docker Push ci
+      run: docker push paparazziuav/pprz-ci
+      
+    - name: Docker Push dev
+      run: docker push paparazziuav/pprz-dev
+