[llvm] workflows/release-binaries: Remove .git directory from artifacts (PR #106310)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

Did you come across this from the article or was there some scanner involved here?

I'm assuming the token by default won't have a large amount of permissions though and should be ephemeral?

Speaking of that, do we want to tack on a
```yaml
permissions:
  contents: read
```

at the top?



https://github.com/llvm/llvm-project/pull/106310