Log Message:
py-execnet: updated to 2.1.0

2.1.0 (2024-04-05)

Added main_thread_only execmodel which is derived from the thread execmodel and \ 
only executes remote_exec calls in the main thread.

Callers of remote_exec must use the returned channel to wait for a task to \ 
complete before they call remote_exec again, otherwise the remote_exec call will \ 
fail with a concurrent remote_exec would cause deadlock error.

Also fixed init_popen_io to use closefd=False for shared stdin and stdout file \ 
descriptors, preventing Bad file descriptor errors triggered by \ 
test_stdouterrin_setnull.

The library is now typed and the typing is exposed to type-checkers.

Re-exported Gateway, Channel, DumpError and LoadError from execnet. The \ 
constructors are private.

Fixed GatewayBase.join() timeout argument getting ignored.

Removed support for Python 3.7.

Added official support for Python 3.12.