[GH] Update contribution docs with how to update lint
[GH] Update contribution docs with how to update lint

This just updates the documentation for how to update the lint baseline.

Test: None, just a documentation change.

This is an imported pull request from https://github.com/androidx/androidx/pull/53.

Resolves #53
Github-Pr-Head-Sha: 3fae96b36279c839b433199397c107d48108dcc1
GitOrigin-RevId: 4de8f6ace1c0966638ac4debce8044c92cce89f2
Change-Id: Iac26680233dfbe8567fc62e5a6676a068a96e1f8

AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx