Updated @storybook/addon-jest README.md installation instructions (#6952)
Updated @storybook/addon-jest README.md installation instructions (#6952)

Updated @storybook/addon-jest README.md installation instructions
storybooks/storybook,storybooks/react-storybook,kadirahq/react-storybook,storybooks/react-storybook,storybooks/react-storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook