Update index.md

Refactor. Fixes a typo of EnvironmentEvent being referred to as EnviromentEvent which leads to developers believing they're using a deprecated class.
Update index.md

Fixes a typo of EnvironmentEvent being referred to as EnviromentEvent which leads to developers believing they're using a deprecated class.
Merge pull request #3 from peterfox/patch-1

Updates documentation to be inline with correct EnvironmentEvent class name