fix(gitlab): catch UNABLE_TO_VERIFY_LEAF_SIGNATURE

lib/platform/gitlab/gl-got-wrapper.ts

@@ -33,7 +33,10 @@ async function get(path: string, options: any) {
     if (err.statusCode >= 500 && err.statusCode < 600) {
       throw new Error('platform-failure');
     }
-    if (err.code === 'ECONNRESET') {
+    if (
+      err.code === 'ECONNRESET' ||
+      err.code === 'UNABLE_TO_VERIFY_LEAF_SIGNATURE'
+    ) {
       throw new Error('platform-failure');
     }
     throw err;