fixed typos in README

[pcoet]

Please add a meaningful description for your change here

I was looking at the new SDK (cool!) and fixed a couple of typos in the README.

@robertwb

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[aaltay]

Thank you @robertwb!

It looks like I forgot to click merge? @pcoet - please ping me directly if your reviews/merging of PRs are delayed. It is easy to miss GH notifications.