Add GitHub audit integration

[legoguy1000]

What does this PR do?

Adds integration to fetch GitHub audit logs

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• If I'm introducing a new feature, I have modified the Kibana version constraint in my package's manifest.yml file to point to the latest Elastic stack release (e.g. ^7.13.0).

Author's Checklist

• [ ]

How to test this PR locally

cd integrations/packages/github
elastic-package build && elastic-package stack down && elastic-package stack up  --version 7.16.0-SNAPSHOT  -d -v && eval "$(elastic-package stack shellinit)" && elastic-package test -v

Related issues

Screenshots

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2021-10-12T20:52:09.084+0000

• Duration: 13 min 8 sec

• Commit: da78bce

Test stats 🧪

Test	Results
Failed	0
Passed	20
Skipped	0
Total	20

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

[P1llus]

/test

[P1llus]

/test

[P1llus]

Just going to see if we can test this against our own Github Account, but the rest looks good!

[legoguy1000]

Just going to see if we can test this against our own Github Account, but the rest looks good!

Sweet. You'll need someone with org:admin role.

[P1llus]

/test

[P1llus]

Works great! tested on our API as well, LGTM!