What is the easiest way to backup PostgreSQL and send backups to Google Drive?
You could try:

https://github.com/andreafabrizi/Dropbox-Uploader

to send your pg_dump output to Dropbox. I got this by Googling script load file dropbox. You may find some of the other scripts more to your liking.

Remember the dba's motto - backup or f*ckup and test, test and test again. Personally, I would recommend a local (speed of recovery) and remote (double-sure) copy (as the Americans say, "belt and suspenders").

It is a bash tool, but then I always assume PostgreSQLers are on a decent operating system :-).

Update - the bash shell can now be used natively on Windows as well since Microsoft appear to be doing more embracing and less smothering of *nix tools!