Removes the htpasswd prerequisite from README

Looks like htpasswd dependency was removed in this commit.
4eccd64e0ff5dd77e24f01a720a576fe24a953a3
Merge pull request #338 from thagikura/patch-2

Removes the htpasswd prerequisite from README
Merge pull request #333 from thockin/valid8

Add validation for Container.Env
Fix wrong json name for Key field