Temporary Fix for Failing MySql2 Contract Tests (#125)

Changes to mysql2 upstream 3.11.5 has caused failures in contract tests.
Currently locking it to 3.11.4 until a fix is implemented.

*Description of changes:*

Locking the package.json in mysql2 to 3.11.4

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contract-tests/images/applications/mysql2/package.json

@@ -10,6 +10,6 @@
   "license": "ISC",
   "description": "",
   "dependencies": {
-    "mysql2": "^3.11.3"
+    "mysql2": "3.11.4"
   }
 }