ci(workflows): disable trigger of workflows for dependabot alerts

.github/workflows/build.yml

@@ -1,6 +1,9 @@
 name: build
 
-on: push
+on:
+  push:
+    branches:
+      - master
 
 jobs:
   build:

.github/workflows/check-deps-security.yml

@@ -1,6 +1,9 @@
 name: snyk
 
-on: push
+on:
+  push:
+    branches:
+      - master
 
 jobs:
   check-deps-security:

.github/workflows/docker-build.yml

@@ -0,0 +1,31 @@
+name: docker
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  docker-build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Rename .env.example
+        run: mv .env.example .env
+
+      - name: Docker build
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}