chore: Add Owlbot config to repository

[holtskinner]

• Add Owlbot config to repository to automatically format code using blacken on Pull Requests.
• Not sure if this was intentionally left out for some reason, feel free to reject if thats the case

[engelke]

Can you explain why this is needed? And get all tests to pass, please.

I'm not familiar with the synthtool library, and could not find documentation to answer my question: what is s.move(templated_files / "noxfile.py") doing. Is the library overloading the division operator?

[kweinmeister]

Just FYI, this was started in an open PR #7810 but not yet completed.

FYI @parthea @loferris

[parthea]

Can you explain why this is needed?

+1. We should add a note explaining what will happen when the owlbot configuration is added (eg. code formatting will run on every PR). We should also update contributors docs to let folks know that owlbot runs automatically on PRs which branched off main, and for branches from forks the owlbot:run label needs to be added for owlbot to run.

I'm not familiar with the synthtool library, and could not find documentation to answer my question: what is
s.move(templated_files / "noxfile.py") doing. Is the library overloading the division operator?

Regretfully, documentation for synthtool is lacking. I've added some answers below but let me know if I can clarify things further

templated_files = gcp.CommonTemplates().py_library()

# Copy the standard noxfile from templated_files
s.move(templated_files / "noxfile.py")

The source code for py_library is here. Regretfully py_library doesn't have a docstring that explains what it does. My understanding is that it returns a path to the googleapis python templates which are part of synthtool.

The source code for s.move is here. s.move() will move a file specified in sources to the current directory.

sources can be a Path, in that case a slash operation is supported.

For example, Path("test") / "testing" works

>>>from pathlib import Path
>>>example_path : Path = Path("test") / "testing"
>>>example_path
PosixPath('test/testing')