Add Dependabot configuration and validate GitHub Actions (#22) [no ci]

* add dependabot file

* validate the action yml file too

Author: jazzsequence

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: composer
+    directory: "/"
+    schedule:
+      interval: weekly
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly

.github/workflows/lint.yml

@@ -4,6 +4,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
+      - uses: jazzsequence/github-action-validator@v1
       - name: Lint
         run: shellcheck bin/*.sh