Release 4.6

[minrk]

We should be about ready to release 4.6, which has some nice fixes and improvements.

• changelog Add changelog 4.6.0 #236
• bump protocol to 5.1 ipykernel currently implements protocol 5.1 #238
• TextIOBase API inherit IOStream from TextIOBase #234
• PID 1 issue affecting docker Disable parent-poller if PID is 1 #233

cc @JamiesHQ

[takluyver]

Is there anything else to do for this? Do you want to push the button?

[minrk]

All set, pushing the button now.

[minrk]

Released