adds release checklist

RELEASE_CHECKLIST.md

@@ -0,0 +1,41 @@
+# 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 the 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%3Acloudflare%2Fwrangler+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 semi-related to something that's been included in the release (point releases can be a little weirder).
+1. Create a new branch "#.#.#" where "#.#.#" is this release's version.
+1. Add this release to the `CHANGELOG.md`. Use the structure of previous
+   entries. If you use VS Code, you can use [this snippet](https://gist.github.com/EverlastingBugstopper/04d1adb99506388ff9d7abd8d0a82bc3) to insert new changelog sections.
+1. Update the version in `Cargo.toml`.
+1. Run `cargo update`.
+1. Run `cargo test`.
+1. Run `cargo build`.
+1. Copy `README.md` to `npm/README.md`
+1. Bump the version number in `npm/package.json`
+1. `cd npm && npm install`
+1. Push up a commit with the `Cargo.toml`, `Cargo.lock`,
+   and `CHANGELOG.md` changes. The commit message can just be "#.#.#".
+1. Request review from the @cloudflare/workers-devexp team.
+1. `git commit --amend` all changes into a single commit.
+1. Once ready to merge, tag the commit by running `git tag -a v#.#.# -m #.#.#`.
+1. Wait for CI to pass.
+1. After CI builds the release binaries and they appear on the [releases page](), click `Edit`, and
+   paste the current release notes from `CHANGELOG.md` and paste it into the release body.
+1. Update the title of the release (not the tag itself) to include the emoji for the current release
+1. Be sure to add any missing link definitions to the release.
+1. Hit the big green Merge button on the release PR.
+1. `git checkout master` and `git pull --rebase origin master`
+1. Run `cargo test`.
+1. `cargo publish`
+1. `cd npm && npm publish`
+1. Tweet.