feat: buf format via stdin

[choplin]

buf now support format files via stdin.

This would be more efficient than the current temp_file settings. (Additionally, temp_file settings don't work out-of-the-box in my environment)

[stefanvanburen]

I don't think it's supported quite yet - there's an open PR for it though. I'd assume it'll make it out in the next release.

[jose-elias-alvarez]

Thanks! Let's wait until the upstream PR has been merged, then we can go ahead and merge this, since I agree it's a big improvement.

[choplin]

Thanks, everyone! Right, I misunderstood the buf behavior. Although this PR worked for me as expected, it didn't format input from stdin but format all proto files on the project defined with buf.yaml and buf.work.yaml. Since the rest proto files were already formatted, it looked to format only the file being edited.

By the way, I added the --stdin flag for bufbuild/buf#1345. I'd be happy if this would be merged when bufbuild/buf#1345 is merged and released.

[choplin]

I'll watch bufbuild/buf#1345, and let you know when it's released.