Changed the default body for a GET request to be "" instead of `{} to fix #394

[danielvaughan]

refs: #394

Got some code for us? Awesome 🎊!

Please include a description of your change & check your PR against this list, thanks!

• [x] There's a clear use-case for this code change
• [x] Commit message has a short title & references relevant issues
• [x] The build will pass (run yarn test and yarn lint)

More info can be found by clicking the "guidelines for contributing" link above.