doc(release): add release checklist

RELEASE_CHECKLIST.md

@@ -0,0 +1,38 @@
+# Release Checklist
+
+This is a list of the things that need to happen during a release.
+
+1. Open the associated milestone. All issues and PRs should be closed. If
+  they are not you should reassign all open issues and PRs to future
+  milestones.
+1. Go through the commit history since last release. Ensure that all PRs
+  that have landed are marked with the milestone. You can use this to 
+  show all the PRs that are merged on or after YYY-MM-DD: 
+  `https://github.com/issues?utf8=%E2%9C%93&q=repo%3Arustwasm%2Fwasm-pack+merged%3A%3E%3DYYYY-MM-DD`
+1. Go through the closed PRs in the milestone. Each should have a changelog
+  label indicating if the change is docs, fix, feature, or maintenance. If
+  there is a missing label, please add one.
+1. Choose an emoji for the release. Try to make it some sort of transition
+  from the previous releases emoji (point releases can be a little weirder).
+1. Create a new branch "#.#.#" where "#.#.#" is the release's version.
+1. Add this release to the `CHANGELOG.md`. Use the structure of previous 
+  entires.
+1. Update the version in `Cargo.toml`.
+1. Update the version number and date in `docs/index.html`.
+1. Run `cargo update`.
+1. Run `cargo test`.
+1. Run `cargo build`.
+1. Push up a commit with the `Cargo.toml`, `Cargo.lock`, `docs/index.html`,
+  and `CHANGELOG.md` changes. The commit message can just be "#.#.#".
+1. Request review from `@ashleygwilliams` and `@drager`.
+1. `git commit --amend` all changes into the single commit.
+1. Once ready to merge, tag the commit with the tag `v#.#.#`.
+1. Wait for the CI to go green.
+1. The CI will build the release binaries. Take the `CHANGELOG.md` release
+  entry and cut and paste it into the release body.
+1. Be sure to add any missing link definitions to the release.
+1. Hit the big green Merge button.
+1. `git checkout master` and `git pull --rebase origin master`
+1. Run `cargo test`.
+1. `cargo publish`
+1. Tweet.