Secure Shell (stable) updated to 0.50

[Mike Frysinger]

i've just released Secure Shell (stable) 0.50 [ext] which adds port forwarding support to WASM.  it also includes a fix for NaCl ssh-agent forwarding when very large messages (8k+) are used.

Secure Shell (nassh) ChangeLog:

# 0.50, 2022-09-25, WASM port forwarding support.

* wassh: sockets: Stub out SO_ERROR.
* wassh: fs: Stub out fd_fdstat_set_flags.
* Update license boilerplate text in source code files.
* relays: Harmonize onWriteSuccess usage.
* wassh: sockets: Implement listening support
* wassh: sockets: Don't warn about unhandled sockets
* wassh: sockets: Implement shutdown() support
* wassh: sockets: Initial accept() support
* wassh: sockets: Initial listen() support
* wassh: sockets: Initial bind() support
* agent: Use correct write count for ssh-agent relay.
* wassh: sockets: Ignore SO_REUSEADDR.
* wasi-js-bindings/wassh: Fix passing debug setting down.
* wassh: sockets: Unify get/set socket option methods.
* wassh: sockets: Tweak chrome.sockets.tcp checks.
* wassh: vfs/sockets: Improve debugging a little more.

-mike