I am not touching github even with aseptic gloves, so I'm not going
to read what they say, but the error message is pretty clear.
To upload ("push", in git parlance), you need to authenticate to
origin (somewhere at github in your case). Up to now, you have been
using https with password for that -- they disabled that method
because they consider it insecure. So you will have to change
accordingly.
The relevant commands on your side are along the lines of
# this removes your disfunctional remote called 'origin'
git remote remove origin
# this re-adds it
git remote add origin <new URL>
BE CAREFUL: find out what <new URL> is BEFORE you do the remove. Your
<new URL> might be something like "git:g...@github.com:your/repo/path"
or similar, depending on the instructions at github.
I won't read them -- github gives me skin rashes.
Cheers & good luck.
--
t