Automated: Add Semgrep github action

.github/workflows/semgrep.yml

@@ -0,0 +1,23 @@
+######################################################################################################################
+# THIS FILE IS AUTOGENERATED. SEE https://github.com/fishbrain/terraform/blob/master/repositories/semgrep.tf         #
+######################################################################################################################
+name: Semgrep
+on:
+  pull_request: {}
+  push:
+    branches: ["master", "main"]
+  schedule:
+    - cron: '0 2 * * 1-6' # scheduled for 02:00 UTC every day except Sunday
+
+jobs:
+  semgrep:
+    name: Scan
+    runs-on: ubuntu-latest
+    container:
+      image: returntocorp/semgrep
+    if: (github.actor != 'dependabot[bot]')
+    steps:
+      - uses: actions/checkout@v4
+      - run: semgrep ci
+        env:
+          SEMGREP_APP_TOKEN: ${{ secrets.SEMGREP_APP_TOKEN }}