Add release.md that follows Featuretools, Woodwork release process

[gsheni]

• We should add a release.md file that follows our other libraries
  • https://github.com/alteryx/woodwork/blob/main/release.md
  • https://github.com/alteryx/featuretools/blob/main/release.md
  • Some parts of this will apply to autonormalize and some parts will not