chore: fixes cs and adds cs checking to travis (firebase#284)

feat: add support for ES256 algorithm (firebase#256)

updates README changelog for v5.0.0 (firebase#166)

Update README for v4.0.0

Update package.xml and README.md for 3.0.0 release

Update README and bump to v2.2.0

Update package.xml

Bump version to 2.0.0

adding version for a stable release

Initial version