Update dependency truffle to v5.11.2

Author: renovate[bot]

package.json

@@ -62,6 +62,6 @@
     "mocha-lcov-reporter": "1.3.0",
     "prettier": "2.1.2",
     "solidity-coverage": "0.7.11",
-    "truffle": "5.1.48"
+    "truffle": "5.11.2"
   }
 }