Python2 reference in environment.conf

This section in the environment.conf:

1. Although HPCC platform includes plugins for both Python2 and Python3, only one may be safely enabled at a time
2. as the Python libraries export the same symbols for both versions. Enabling both may lead to unpredicatable results
3. including segfaults or undefined symbol errors.
   #
4. If you would prefer to use python2 and disable python3, change the line below to read
5. additionalPlugins=python2
   #
6. Multiple paths can be specified (separate with :, or ; on Windows).
7. Relative paths are assumed to be relative to ${INSTALL_DIR}/versioned
   additionalPlugins=python3

Refers to installing Python2.
see https://track.hpccsystems.com/browse/HPCC-24173

If python2 no longer supported, should remove this option from the environment.conf