v0.2.3

• Update CI
• Update build.sh
• Rename project shellsrv -> ssrv
• Rename env var SSRV_ALLOC_PTY -> SSRV_PTY
• Rename env var SSRV_NO_ALLOC_PTY -> SSRV_NO_PTY
• Rename env var SSRV_SOCKET -> SSRV_SOCK
• Rename arg -server -> -srv
• Rename arg -socket -> -sock
• Rename arg -version -> -v
• Add the ability to specify all variables with an exception:

ssrv -env all-:MY_VAR -uenv all-:MY_VAR1

in this example, we send all local variables except MY_VAR to the server and unset all variables on the server except MY_VAR1