Run the Docker build workflow when we touch project or toolchain metadata (#11938)
I noticed that https://github.com/astral-sh/uv/pull/11936 did not run
the Docker builds, nor did #11934
We should run these when the relevant files change so there aren't
surprises at release time!
Updates the `build-binaries` workflow to include toolchain version
changes and `.cargo/config.toml` changes too.