docs: update readme

fix: no resource found for `fsimportexistingdocs` (firebase#2018) (fi…

…rebase#2019)

fix(firestore-bigquery-export): disable backfill temporarily (firebas…

…e#2005)

* fix(firestore-bigquery-export): disable onInstall backfill

* chore(firestore-bigquery-export): increment CHANGELOG and version

Merge pull request firebase#1986 from firebase/next

Merge pull request firebase#1986 from firebase/next

Merge pull request firebase#1936 from firebase/next

Merge pull request firebase#1936 from firebase/next

Merge pull request firebase#1936 from firebase/next

Merge pull request firebase#1915 from firebase/next

release: January

Merge pull request firebase#1915 from firebase/next

release: January