docs (readme)- fix broken links to Gurdrails website

[medichecks-subrata]

Updated the link to the Supported LLM Models section in the README.

Description

README update.
Fixed broken link!

Related Issue(s)

NA

Verification

NA

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Checklist

• I've read the CONTRIBUTING guidelines.
• This PR links to a triaged issue assigned to me.
• My PR title follows the project commit convention.
• I've updated the documentation if applicable.
• I've added tests if applicable.
• I've noted any verification beyond CI and any checks I couldn't run.
• I did not update generated changelog files manually.
• I addressed all CodeRabbit, Greptile, and other review comments, or replied with why no change is needed.
• @mentions of the person or team responsible for reviewing proposed changes.