Config to improve usability

[hickford]

Sharing config I find improves usability on Linux:

Cache credentials in memory and extend maximum cache time to 20 hours. This means you have to authenticate at most once per day (assuming you don't log out or restart).

git config --global credential.credentialStore cache
git config --global credential.cacheoptions "--timeout 72000"

Set preferred authentication mode to browser (rather than manually choose each time) and disable GUI helper (slow extra step).

git config --global credential.githubauthmodes browser
git config --global credential.githubhelper ""