Add PR checks (#14)

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+

.github/workflows/lint.yaml

@@ -0,0 +1,16 @@
+name: Lint
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        name: Checkout
+      - name: Run ShellCheck
+        uses: ludeeus/action-shellcheck@master