Release process

This document simply outlines the release process:

Remove .dev extension from VERSION
Run make clean test to ensure all tests pass from scratch and the CI is green
Ensure CHANGELOG is updated and tag release version with timestamp in it
Commit changes above and update stable branch
Create tag from master branch
Release new docs with make release_docs, update elixir-lang.org
Release new zip with make release_zip, push new zip to Elixir's elixir-lang.org/packages.html
Push package to expm with expm publish package.exs
After release, bump versions and add .dev back

Places where version is mentioned