Remove old codeql workflow, add dependabot checks for Actions

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    groups:
+      github-actions:
+        patterns:
+          - "*"

.github/workflows/codeql-analysis.yml

@@ -1,35 +0,0 @@
-name: "Code scanning - action"
-
-on:
-  push:
-  pull_request:
-  schedule:
-    - cron: '0 12 * * 4'
-
-jobs:
-  CodeQL-Build:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v2
-      with:
-        # We must fetch at least the immediate parents so that if this is
-        # a pull request then we can checkout the head.
-        fetch-depth: 2
-
-    # If this run was triggered by a pull request event, then checkout
-    # the head of the pull request instead of the merge commit.
-    - run: git checkout HEAD^2
-      if: ${{ github.event_name == 'pull_request' }}
-
-    # Initializes the CodeQL tools for scanning.
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
-
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
-
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1