update frozen_lake docs

[Arcify]

#2618 Changed env.make version to v1 and made some other small improvements to the documentation to make it more understandable.

I am however, not sure what to change in version info, as v0 (the only version before this one) is already mentioned in the version history.

[Arcify]

Please let me know if there is anything else that is unclear/missing, I would be happy to modify the pull request :)

[trigaten]

Please let me know if there is anything else that is unclear/missing, I would be happy to modify the pull request :)

Can you add what changed in v1?

Other envs do: http://www.gymlibrary.ml/pages/environments/classic_control/acrobot

[Arcify]

Please let me know if there is anything else that is unclear/missing, I would be happy to modify the pull request :)

Can you add what changed in v1?

Other envs do: http://www.gymlibrary.ml/pages/environments/classic_control/acrobot

The only change I could find to v1 is a few bug fixes in the rewards:
https://github.com/openai/gym/releases (0.19)
#2205

I have added this to my pull requested

[trigaten]

LGTM

[jkterry1]

I'm merging this so it's in the docs string for the release, please create another PR for any addition changes agreed upon