Any time you want to show me a 100% future-proof algorithm for sensitive-info detection that works across any/all code on github, I'd be happy to toss my hat in and say, "I was wrong", until then, people will never ever beat 0days they don't know exist (0day being more than just a SW exploit). Just do.not.commit.sensitive.info.to.github. Period. That is the only sure way to not mess it up. Software only executes what is in the code, regardless of how nonsensical it is (aka, your code will not save you from messing up, something something something, PEBKAC)
I'm not arguing it's "impossible to play this game" It's 100% possible to play it when and how you'd like. I'm discussing the rate of "did I win (read: not get pwnd)?" It's cat and mouse of automation for vulnerable/sensitive info ... but all of that is rendered moot if you ... wait for it ... don't commit it to Github which would mean it wouldn't get to Github's API which means it wouldn't appear in 3rd party services sucking the firehose from Github cloud-y silicon teet.
And expanding on this ... committing your passwords and sensitive info to your code-repo is so misguided it's actually funny. What happens if you have an employee and they go off the deep end? Whoops, gotta rotate all those passwords/credentials/un-fuck every branch/resync dev's machines/etc. Keeping that sensitive info in a private, self-hosted, well-maintained internal repo (with strong ACLs, especially wrt server/hosting environments) will go significantly further for your team's security than submitting a feature request to a company to stop you from making arbitrary mistakes every so often.