chore(security): secret scanning + dependabot cooldown (#348)

* chore(security): add gitleaks secret scanning workflow

* chore(security): add dependabot with 7-day cooldown

Author: ikekurghinyan

.github/dependabot.yml

@@ -0,0 +1,20 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+    cooldown:
+      default-days: 7
+      exclude:
+        - toptal/*
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+    cooldown:
+      default-days: 7
+      exclude:
+        - toptal/*

.github/workflows/security-scan.yml

@@ -0,0 +1,8 @@
+name: Secret Scan
+
+on:
+  pull_request:
+
+jobs:
+  call_secret_scanning:
+    uses: toptal/actions/.github/workflows/security-scan.yml@v3.6.3