Make codecov.io remember github authentication sessions for longer time

[ssbarnea]

Describe the bug

I love codecov.io and use it daily but I often see myself having to login again and again at least once a day.

As a developer I would expect to not have to re-authenticate with github if I already did it in the last ~7 days with the same browser.

To Reproduce

Revisit codecov.io after two of using it first time, you will be browsing as guest and you will have to manually press login button to login.

Expected behavior

Remember login sessions for 7 days.

Additional context

I tried to search about how Github SAML authentication works but I was not able to find too much information. I supposed that there is a configurable session length and even if they might have a small limit to the session duration, it should be possible to remember your current account in a cookie and re-trigger a login when the session is expired.