Add version tag to be referenced by pre-commit

[b1ackviking]

When I try to use the hook as described in the readme, pre-commit issues the following warning message:

[WARNING] The 'rev' field of repo 'https://github.com/doublify/pre-commit-clang-format'
          appears to be a mutable reference (moving tag / branch). 
          Mutable references are never updated after first install and are not supported. 
          See https://pre-commit.com/#using-the-latest-version-for-a-repository for more details.

This basically means that using rev: master is wrong.

Although the hook does not seem to be frequently updated, it is sad to see this warning every time I commit. I suggest adding a 1.0 tag to the current HEAD of the repository.

[henryiii]

You can also just put an commit SHA here. But yes, pre-commit caches assuming the rev will never change, so you should never use master/main.

[okainov]

+1 here, would be helpful