Add linting at github actions

.github/workflows/main.yml

@@ -14,6 +14,12 @@ jobs:
     steps:
       - uses: actions/checkout@v1
 
+      - name: shellcheck
+        uses: ludeeus/action-shellcheck@master
+
+      - name: hadolint
+        uses: brpaz/hadolint-action@master
+
       - name: Build image
         run: ./build.sh