An update_sla() function

[kambleakash0]

Description

Wrote an update_sla() function based on the issue #250
Since CDM versions after 5.1 all have put the patch call for modifying SLA details in the V3, I have used the same call for those versions and versions for prior to 5.2 I have used the V1 put call to modify SLA parameters.

Related Issue

create update_sla() function to allow changing settings of an existing SLA #250

Motivation and Context

Provides a handy function call to users in case they want to modify an already created SLA.

How Has This Been Tested?

Tried to manually test it on a Rubrik cluster with CDM version 8.0.1-21908 but facing some issue.
Maybe due to V3 not being one of the valid API versions but facing the same issue even after I added 'v3' to the 'valid_api_versions' list inside '_api_validation()' from 'rubrik_cdm.py.Connect' class:
valid_api_versions = ['v1', 'v2', 'internal', 'v3']

Screenshot of the issue faced:

Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

Go over all the following points, and put an x in all the boxes that apply. If you're unsure about any of these, don't hesitate to ask. We're here to help!

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTION document.
• I have updated the CHANGELOG file accordingly for the version that this merge modifies.
• I have added tests to cover my changes.
• All new and existing tests passed.