chore: Update GitHub CI workflows

.github/dependabot.yml

@@ -9,3 +9,7 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'daily'

.github/workflows/semgrep.yml

@@ -1,25 +1,49 @@
-name: semgrep
+name: Semgrep
 
 on:
-  pull_request_target: {}
-
+  merge_group:
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
   push:
-    branches: [main]
-
+    branches:
+      - main
   schedule:
-    - cron: '30 0 1,15 * *'
+    - cron: "30 0 1,15 * *"
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
 
 jobs:
-  scan:
+  authorize:
+    name: Authorize
+    environment: ${{ github.actor != 'dependabot[bot]' && github.event_name == 'pull_request_target' && github.event.pull_request.head.repo.full_name != github.repository && 'external' || 'internal' }}
     runs-on: ubuntu-latest
+    steps:
+      - run: true
+
+  run:
+    needs: authorize # Require approval before running on forked pull requests
+
+    name: Check for Vulnerabilities
+    runs-on: ubuntu-latest
+
     container:
       image: returntocorp/semgrep
 
-    # Skip any PR created by dependabot to avoid permission issues
-    if: (github.actor != 'dependabot[bot]')
     steps:
-      - uses: actions/checkout@main
-      - name: Run Semgrep to check for vulnerabilities
-        run: semgrep ci
+      - if: github.actor == 'dependabot[bot]' || github.event_name == 'merge_group'
+        run: exit 0 # Skip unnecessary test runs for dependabot and merge queues. Artifically flag as successful, as this is a required check for branch protection.
+
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha || github.ref }}
+
+      - run: semgrep ci
         env:
           SEMGREP_APP_TOKEN: ${{ secrets.SEMGREP_TOKEN }}