JavaScript and Python: unique file names for version.txt files

[greg-at-moderne]

What's changed?

Rename the special version.txt files baked into rewrite-python and rewrite-javascript JAR files.
New names are unique - different for JS and Python.

What's your motivation?

Prevent JavaScript RPC server from reading the Python one (and vice versa).

The following has been observed in CI of one of the derived projects:

Error output:
      npm error code ETARGET
      npm error notarget No matching version found for @openrewrite/rewrite@8.75.0.dev20260226090025.
      npm error notarget In most cases you or one of your dependencies are requesting
      npm error notarget a package version that doesn't exist.
      npm error A complete log of this run can be found in: /home/runner/.npm/_logs/2026-02-26T12_23_59_857Z-debug-0.log