Added git workflow to build and publish dev docker image

.dockerignore

@@ -0,0 +1,13 @@
+bump_version.sh
+docker
+docs
+*.git
+*.gitignore
+includes/settings.php
+java
+Makefile
+release-files
+tests
+TODO
+vendor
+ws

.github/workflows/docker-dev.yml

@@ -0,0 +1,38 @@
+name: Publish Dev Docker Image
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  push_dev_to_registry:
+    name: Push Development Docker image to Docker Hub
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Extract Commit Hash
+        id: extract_hash
+        run: echo "::set-output name=hash::$(git rev-parse --short HEAD)"
+
+      - name: Get WebCalendar Version
+        run: echo "WEBCALENDAR_VERSION=$(./bump_version.sh -p)" >> $GITHUB_ENV
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          file: ./docker/Dockerfile-php8
+          push: true
+          tags: |
+            ${{ secrets.DOCKER_HUB_USERNAME }}/webcalendar:${{ env.WEBCALENDAR_VERSION }}-${{ steps.extract_hash.outputs.hash }}-php8-apache-dev
+            ${{ secrets.DOCKER_HUB_USERNAME }}/webcalendar:dev-php8-apache
+            ${{ secrets.DOCKER_HUB_USERNAME }}/webcalendar:dev
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v1 
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}