dev: developブランチをDocker Hubにpushするように

Resolve #7845

.github/workflows/docker-develop.yml

@@ -0,0 +1,33 @@
+name: Publish Docker image (develop)
+
+on:
+  push:
+    branches:
+      - develop
+  workflow_dispatch:
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to Docker Hub
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v2
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: misskey/misskey
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and Push to Docker Hub
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: develop
+          labels: develop