Update typescript/looker/README.md
Update typescript/looker/README.md

Grammatical correction

Co-Authored-By: Joseph Axisa <5bb0af57f42d7b5b142c660476eb538557084338@looker.com>
looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen,looker-open-source/sdk-codegen