Add security-gates workflow and update README

Author: KaanAdas-TY

.github/workflows/security-gates.yml

@@ -0,0 +1,22 @@
+name: Security Gates
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Validate Workflow
+        run: echo "Validation successful"
+
+  security-gates:
+    uses: Trendyol/security-actions/.github/workflows/security-gates.yml@master
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+    secrets: inherit