[FEATURE REQUEST] A way to update git_pillar_password on time interval

[boyadzhievb]

Is your feature request related to a problem? Please describe.
To sync pillars from Github for authentication we need to use HTTPS with Authentication Tokens
generated by GitHub App on let say every 15 minutes. A token is valid for 30 minutes and
must be regenerated after that.

Describe the solution you'd like
Reread git_pillar_password every 10 minutes(parameterized time like git_pillar_update_interval)
to get new value which we updated in master file by using other means
(a script that regenerates the token and replace it in the master file)

Describe alternatives you've considered
keep git credentials in different file but again rereading them on interval

Please Note
If this feature request would be considered a substantial change or addition, this should go through a SEP process here https://github.com/saltstack/salt-enhancement-proposals, instead of a feature request.