Merge from aws-lambda-runtime-interface-emulator/develop (aws#40)

* Pull upstream changes (aws#34)

* Pull upstream changes 2021/06 (aws#39)

* docs: Fix ordering of options in example (aws#36)

Co-authored-by: Jon Colverson <[email protected]>

Fix integ tests (#4)

Co-authored-by: Jacob Fuss <[email protected]>