Updating README.md file for fixing some typo

[NayeemShaMd]

I have found some type in the README.md file. So updated those.

Checklist

I applicable, I acknowledge that I have:

• Read the contributing guide
• Ran terraform fmt on all modified files
• Regenerated the relevant README.md files using tools/tfdoc.py
• Made sure all relevant tests pass

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[NayeemShaMd]

@ludoo Sorry for tagging. I am a new contributor. I have seen you in multiple threads which is why asking for your help regarding this. What else do I need to do here?

[juliocc]

@NayeemShaMd you're good to go. Let's wait the checks to pass.