The simple strategy just overwrites the contents of version-file with X.Y.Z. This is a problem for my usecase because I need this file to contain v.X.Y.Z.

I can't use the extra-filesmethod discussed in some other issues because I rely on this file only containing the version string, putting the x-release-please-version flag in my version.txt is going to break many places where i cat this file and expect only the version in the content.

I'm proposing that if the version file contains a version already, then we just update the version in place like we do for x-release-please-version, rather than overwrite the file. I've implemented this solution in #2537