JPype 1.2.0

• Added builds for Python 3.9. Python 3.9 on Windows is currently failing
  due to issue in Python.

• Fixed bug when importing from multi-release jars. The directory was
  being truncated to only those classes in the overlay.

• addClassPath can add jar files after the JVM is started. The default
  loader for JPype class is org.jpype.classloader.DynamicClassLoader.

• Build support of z/OS added.

• Bug causing ambiguity between primitives and variadic arguments in method
  resolution was corrected.

• Boolean was inadvertently left out of method resolution. boolean
  now properly matched with boxed types.

• Support for PyInstaller was added.