ORGANIZATION is always required

[timdittler]

Contrary to the README, the env var ORGANIZATION is always required. Otherwise the action will fail with

Traceback (most recent call last):
  File "/action/workspace/cleanowners.py", line 206, in <module>
    main()
  File "/action/workspace/cleanowners.py", line [8](https://github.com/Staffbase/infrastructure/actions/runs/8158526447/job/22300640673?pr=5510#step:4:9)[9](https://github.com/Staffbase/infrastructure/actions/runs/8158526447/job/22300640673?pr=5510#step:4:10), in main
    if not github_connection.organization(organization).is_member(username):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.[12](https://github.com/Staffbase/infrastructure/actions/runs/8158526447/job/22300640673?pr=5510#step:4:13)/site-packages/github3/github.py", line 1688, in organization
    json = self._json(self._get(url), 200)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/github3/models.py", line [16](https://github.com/Staffbase/infrastructure/actions/runs/8158526447/job/22300640673?pr=5510#step:4:17)1, in _json
    raise exceptions.error_for(response)
github3.exceptions.NotFoundError: 404 Not Found

[jmeridth]

@timdittler you cool if I get a PR up for this? or were you planning to go after it?

[timdittler]

@jmeridth Of course. I would be happy if you fixed it!

[jmeridth]

@timdittler reading the code more, I believe we currnetly don't want to make ORGANIZATION required. As the README currently reads, a user can provide a REPOSITORY environment variable instead of ORGANIZATION that includes specific repositories, from potentially multiple organizations. Currently at least one of them is required.

What I'm thinking:

If ORGANIZATION environment variable is provided:

• focus on that single organization's repositories

if REPOSITORY environment variable list is provided instead:

• verify that each org prefix on the repositories is an actual org
• use that org as the organization variable in this line of code (the one causing the error in this issue)

note: currently, if both environment variables are used, ORGANIZATION has priority and REPOSITORY is ignored. (future, allow both and parse accordingly)

Gonna try out a PR.