[LP#1949913] Fix pep8 issue and document requirer side schema

[addyess]

• fixes pep8 violation in providers.py - line too long
• adds more docs to the readme.md

[addyess]

@ajkavanagh -- i tried this out but it yields errors in vault:

hvac.exceptions.InvalidPath: 1 error occurred:
        * unsupported path

, on post http://127.0.0.1:8220/v1/auth/approle/role/charm-c42ad607-4a0d-4d3f-8615-18d0a4b6eabe%3Akubernetes-control-plane-0

that colon manifests in an invalid URL

I think i will revert to a hyphen but leave the documentation

[ajkavanagh]

@ajkavanagh -- i tried this out but it yields errors in vault:

hvac.exceptions.InvalidPath: 1 error occurred:
        * unsupported path

, on post http://127.0.0.1:8220/v1/auth/approle/role/charm-c42ad607-4a0d-4d3f-8615-18d0a4b6eabe%3Akubernetes-control-plane-0

that colon manifests in an invalid URL

I think i will revert to a hyphen but leave the documentation

That seems reasonable. Thanks for looking into it. I guess the : would need to be escaped. _ might have worked, but no need to go change it now!