Update munki_makecatalogs.py

[kbrewersq]

It looks like you updated this to stop looking defining python, but missed the main where it checks for the existence of the python variable.

error i see on v1.14.1

Run Munki Makecatalogs...................................................Failed
- hook id: munki-makecatalogs
- exit code: 1

Traceback (most recent call last):
  File "/Users/kbrewer/.cache/pre-commit/repoehdjx6fz/py_env-python3.12/bin/munki-makecatalogs", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/kbrewer/.cache/pre-commit/repoehdjx6fz/py_env-python3.12/lib/python3.12/site-packages/pre_commit_hooks/munki_makecatalogs.py", line 38, in main
    elif not os.path.isfile(python):
                            ^^^^^^
NameError: name 'python' is not defined

[homebysix]

Good catch, thanks!