Ensure version.h is recreated each build. (#16188)

lib/python/qmk/cli/generate/version_h.py

@@ -20,6 +20,9 @@ def generate_version_h(cli):
     version_h = create_version_h(cli.args.skip_git, cli.args.skip_all)
 
     if cli.args.output:
+        cli.args.output.parent.mkdir(parents=True, exist_ok=True)
+        if cli.args.output.exists():
+            cli.args.output.replace(cli.args.output.parent / (cli.args.output.name + '.bak'))
         cli.args.output.write_text(version_h)
 
         if not cli.args.quiet: