ci: add Security issue template

.gitlab/issue_templates/Security Vulnerability.md

@@ -0,0 +1,12 @@
+<!-- ⚠️  STOP: Do NOT use this template for security vulnerabilities.
+Email security@pezkuwichain.io instead. See SECURITY.md. -->
+
+## DO NOT USE THIS TEMPLATE FOR SECURITY ISSUES
+
+Please email **security@pezkuwichain.io** with details.
+
+See [SECURITY.md](../SECURITY.md) for the full disclosure policy.
+
+/label ~T-security ~P0-critical ~audit-required
+/confidential
+