updated readme with new documentation link

[sanalpanicker]

Fixes #

Additional description

updated readme with new documentation link

CONTRIBUTOR checklist (do not remove)

Please complete for every pull request

• First-time contributors should sign the Contributor License Agreement. It's a fancy way of saying that you are giving away your contribution to this project. If you haven't before, wait a few minutes and a bot will comment on this pull request with instructions.
• npm run lint:fix has been run and linting passes.
• Mocha, Jest (Storyshots), and components/component-docs.json CI tests pass (npm test).
• Tests have been added for new props to prevent regressions in the future. See readme.
• Review the appropriate Storybook stories. Open http://localhost:9001/.
• Review tests are passing in the browser. Open http://localhost:8001/.
• Review markup conforms to SLDS by looking at DOM snapshot strings.

REVIEWER checklist (do not remove)

• CircleCI tests pass. This includes linting, Mocha, Jest, Storyshots, and components/component-docs.json tests.
• Tests have been added for new props to prevent regressions in the future. See readme.
• Review the appropriate Storybook stories. Open http://localhost:9001/.
• The Accessibility panel of each Storybook story has 0 violations (aXe). Open http://localhost:9001/.
• Review tests are passing in the browser. Open http://localhost:8001/.
• Review markup conforms to SLDS by looking at DOM snapshot strings.

Required only if there are markup / UX changes

• Add year-first date and commit SHA to last-slds-markup-review in package.json and push.
• Request a review of the deployed Heroku app by the Salesforce UX Accessibility Team.
• Add year-first review date, and commit SHA, last-accessibility-review, to package.json and push.
• While the contributor's branch is checked out, run npm run local-update within locally cloned site repo to confirm the site will function correctly at the next release.

[welcome]

Thanks for opening this pull request! 💯

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[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @sanalpanicker-zz to sign the Salesforce Inc. Contributor License Agreement.

[welcome]

Congrats on merging your first pull request to Design System React! 🎉
If you have a moment, please fill out this five question survey, we would appreciate it.
On behalf of Salesforce's customers, partners, product specialists and employees, we would like offer sincere thanks and appreciation for helping make our user experience better. We look forward to working with you more in the future.
This definitely calls for a high five!

[interactivellama]

https://github.com/sanalpanicker is a current Salesforce employee. I'm going to override the CLA app and merge.