README may be incorrect about vending XCHammer.app

Hello! The [README](https://github.com/pinterest/xchammer/blob/c6886f29cd81f94a365190e501416b3d81c9b965/README.md) states that

> _Pinterest vendors XCHammer.app for reproducibility and simplicity._

But I cannot locate an official release of `XCHammer.app` in this repository. Some of the samples contain symlinks to `xchammer.app`, but I assume those aren't official. Does the README need to updated?

For context, I was trying to reference `XCHammer.app/Contents/Resources` in a Bazel repo rule to avoid having to install XCHammer via `make install` and instead download the binary on the fly when calling `bazel build ...`. Is this approach possible and/or supported?

Thanks!