fix readme typos

[cha147]

The issue or feature being addressed

• No issue

Details on the issue fix or feature implementation

• fix a few typos in README

Confirm the following

• [ ] I have ensured that I have merged the latest changes from the dev branch
• [ ] I have successfully run a local build
• [ ] I have included unit tests for the issue/feature
• [ ] I have included the github issue number in my commits