v0.9.22

PythonCall v0.9.22

Diff since v0.9.21

Merged pull requests:

• Require a compatible openssl version (#523) (@lassepe)
• More thread-safe GC (#529) (@cjdoris)
• simplify GIL handling (#530) (@cjdoris)
• GIL functions for genuine multi-threading (#535) (@cjdoris)

Closed issues:

• Libraries loaded via _jll packages are visible inside PythonCall environment. (#519)