Remove PyGithub dependency

[austin-owensby]

Summary

Remove the unused PyGithub dependency and make additional small updates.

Changes

• Remove creation of Github instance object because it's not referenced after it's creation
• Raise an exception when attempting to access the now deprecated gh property
• Remove the GitHub token which was only used to create a GitHub instance object which has now been removed
• Remove PyGithub dependency now that all references to it's use are removed
• Add requests dependency which was previously installed with PyGithub
• Replace deprecated utcfromtimestamp in unit tests
• Add .gitignore to prevent unwanted files from making it into the code
• Correct typos to increase professionalism of code

Impacts

1. Because the connection to PyGithub has been removed, issue Make GITHUB_TOKEN unnecessary if private key is provided #5 is no longer needed.
2. In that issue, it links to an external PR: Added development setup instructions to README.md EESSI/eessi-bot-software-layer#2 (comment) where it mentions that EESSI's requirement for a GitHub token comes from PyGHee's requirement. Now that this is being removed, EESSI should be reviewed to see if it's GITHUB_TOKEN requirement can also be removed.

[boegel]

@austin-owensby Thank you for the contribution!

After a quick glance I think the changes you propose make sense, but I need to take a closer look at it and also try to remember why I introduced the self.gh attribute, since that's a breaking change to the PyGHee API, some projects that use PyGHee may be assuming that self.gh is still there.

I think it makes sense to have a gh property that raises an error to mention that this was removed, with some guidance on what to do instead (use PyGithub yourself to create a github.Github instance), do you mind looking into that too?

Also, out of interest: what triggered you to look into this, are you using PyGHee for something?

[boegel]

Suggested change

	* Define an environment variables for the [GitHub app secret token](https://docs.github.com/en/developers/webhooks-and-events/securing-your-webhooks):
	* Define an environment variable for the [GitHub app secret token](https://docs.github.com/en/developers/webhooks-and-events/securing-your-webhooks):

[boegel]

The datetime documentation recommends to use timezone.utc here, so let's do so?

Suggested change

	timestamp = datetime.datetime.fromtimestamp(int(event_info['timestamp_raw'])/1000., datetime.UTC)
	timestamp = datetime.datetime.fromtimestamp(int(event_info['timestamp_raw'])/1000., tz=datetime.UTC)

[austin-owensby]

datetime.UTC is an alias for datetime.timezone.utc
https://docs.python.org/3/library/datetime.html#datetime.UTC

[boegel]

OK, makes sense, but I'm still in favor of adding the tz= to make it explicit we're setting an optional value

[austin-owensby]

Updated 👍

[austin-owensby]

@austin-owensby Thank you for the contribution!

After a quick glance I think the changes you propose make sense, but I need to take a closer look at it and also try to remember why I introduced the self.gh attribute, since that's a breaking change to the PyGHee API, some projects that use PyGHee may be assuming that self.gh is still there.

I think it makes sense to have a gh property that raises an error to mention that this was removed, with some guidance on what to do instead (use PyGithub yourself to create a github.Github instance), do you mind looking into that too?

Also, out of interest: what triggered you to look into this, are you using PyGHee for something?

Yes I can look into that.

At work we were looking for a python library that could handle Webhooks from a GitHub App and make API calls to GitHub using the GitHub app's auth. This library popped up while Googling for something to use.

I think ultimately because our client is very stingy about GPL licenses, we won't end up using it, but I figured I'd hop in and make a small update.