Thrift 0.13.0 does not work with JDK8

Thrift 0.13.0 does not work with JDK8, as it is compiled with JDK11. Even though the source version is JDK8, incorrect byte code is generated for various ByteBuffer methods, e.g.:

Exception in thread "TAsyncClientManager#SelectorThread 22" java.lang.NoSuchMethodError: java.nio.ByteBuffer.rewind()Ljava/nio/ByteBuffer;

The fix is suggested in this blog post: https://www.morling.dev/blog/bytebuffer-and-the-dreaded-nosuchmethoderror/

We can add the release flag for 1.8 (-release=8).