Broken detection when using Java 16+

[mideuger]

Java 16+ broke the N+1 query detection, it seems that the proxy's package has changed.

I've tested locally and setting the value of PROXY_METHOD_PREFIX to jdk.proxy2 instead of com.sun.proxy in those versions does the trick.

I would happily submit a PR that checks the Java runtime version and set the PROXY_METHOD_PREFIX accordingly if that's an acceptable solution.