Creates a step for writing data to paths relative to the build root, mutating the project's source files.
This build step was designed not to be used during the normal build process, but rather as a utility run by a developer with intention to update source files, which will then be committed to version control.
Example use cases:
pub fn addUpdateSourceFiles(b: *Build) *Step.UpdateSourceFiles
pub fn addUpdateSourceFiles(b: *Build) *Step.UpdateSourceFiles {
return Step.UpdateSourceFiles.create(b);
}