Add upload git metadata config parameter to README.md

[thedavl]

What does this PR do?

this prev PR (which has been included in the recent release) added a new uploadGitMetadata config parameter which defaults to true. Update docs to reflect this, and add a note that users should set this config to false if they have the Datadog github integration.

Motivation

Update docs to reflect recent config changes

Testing Guidelines

Additional Notes

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

[codecov-commenter]

Codecov Report

Merging #348 (fb5abff) into master (0f15029) will not change coverage.
The diff coverage is n/a.

❗ Current head fb5abff differs from pull request most recent head 1fc930b. Consider uploading reports for the commit 1fc930b to get more accurate results

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  Files          11       11           
  Lines         789      789           
  Branches      238      238           
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  Hits          593      593           
  Misses        147      147           
  Partials       49       49           

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