Update parse_versions.py to properly receive input

[mvlassis]

Closes #1069.

This PR updates the parse_versions.py script to properly receive input from the arguments. It writes the output to the GITHUB_OUTPUT file.

Also, the default value in the parse_versions() function has been removed, so calling the script without any arguments raises an appropriate exception.

Example run that was successful: here

To test:

• Run the Deploy to AKS and Deploy to EKS actions from this branch, with non-default arguments (e.g. 1.8, latest)

Some examples of runs are here, here, and here.

[mvlassis]

Hey @mvlassis this works but I think we can keep the default arguments option. I expect if no bundle version is given, for the action to run the tests for all the supported bundles. Do you think there's value to removing the default?

Small note: the PR description links the incorrect issue

I didn't explain that well, currently the workflow receives the bundle_version input that is required and has a default value. The parse_versions.py script is called with that input as the argument. Since the input bundle_version is required as seen in this line, that means that checking for an empty input in parse_versions.py should be treated as an error. Removing the check for empty input in parse_versions.py removes us having to write the default value in 2 places (both the .yaml action file and in parse_versions.py), thus reducing the amount of stuff we have to change each time :)