Add automated release setup.

* Add `release-it`, `release-it-lerna-changelog`, and
  `release-it-yarn-workspaces` (and configuration).
* Remove bespoke `bin/publish.js` in favor of using shared logic in
  [release-it-yarn-workspaces](https://github.com/rwjblue/release-it-yarn-workspaces)
* Remove custom `changelog` `package.json` script (no longer needed)

release-it configuration explanation:

* `hooks.before:bump` ensures that we build before publishing
* `release-it-lerna-changelog` runs `lerna-changelog` prompts (with
  $EDITOR) for manual tweaks/changes then prepends to CHANGELOG.md.
* `release-it-yarn-workspaces` uses a bit of a non-standard publishing
  setup because the packages in this repo actually _publish_ from
  `dist/` (**not** from the configured yarn workspaces). In order to
  accomplish that (and ensure everything else is updated) we have to
  override defaults for:
  * `workspaces` to specify the workspaces in `dist/` instead of
    `packages/`
  * `additionalManifests.dependencyUpdates` to ensure the source
    packages in the repo (in `packages/*/*`) are updated to depend
    on the latest versions of our own packages.
  * `additionalManifests.versionUpdates` to ensure the source
    packages in the repo (in `packages/*/*`) are updated to the
    latest versions.

RELEASE.md

@@ -0,0 +1,67 @@
+# Release
+
+Releases are mostly automated using
+[release-it](https://github.com/release-it/release-it/) and
+[lerna-changelog](https://github.com/lerna/lerna-changelog/).
+
+
+## Preparation
+
+Since the majority of the actual release process is automated, the primary
+remaining task prior to releasing is confirming that all pull requests that
+have been merged since the last release have been labeled with the appropriate
+`lerna-changelog` labels and the titles have been updated to ensure they
+represent something that would make sense to our users. Some great information
+on why this is important can be found at
+[keepachangelog.com](https://keepachangelog.com/en/1.0.0/), but the overall
+guiding principle here is that changelogs are for humans, not machines.
+
+When reviewing merged PR's the labels to be used are:
+
+* breaking - Used when the PR is considered a breaking change.
+* enhancement - Used when the PR adds a new feature or enhancement.
+* bug - Used when the PR fixes a bug included in a previous release.
+* documentation - Used when the PR adds or updates documentation.
+* internal - Used for internal changes that still require a mention in the
+  changelog/release notes.
+
+
+## Release
+
+Once the prep work is completed, the actual release is straight forward:
+
+* First ensure that you have `release-it` installed globally, generally done by
+  using one of the following commands:
+
+```
+# using https://volta.sh
+volta install release-it
+
+# using Yarn
+yarn global add release-it
+
+# using npm
+npm install --global release-it
+```
+
+* Second, ensure that you have installed your projects dependencies:
+
+```
+yarn install
+```
+
+* And last (but not least 😁) do your release. It requires a
+  [GitHub personal access token](https://github.com/settings/tokens) as
+  `$GITHUB_AUTH` environment variable. Only "repo" access is needed; no "admin"
+  or other scopes are required.
+
+```
+export GITHUB_AUTH="f941e0..."
+release-it
+```
+
+[release-it](https://github.com/release-it/release-it/) manages the actual
+release process. It will prompt you to to choose the version number after which
+you will have the chance to hand tweak the changelog to be used (for the
+`CHANGELOG.md` and GitHub release), then `release-it` continues on to tagging,
+pushing the tag and commits, etc.

package.json

@@ -19,7 +19,6 @@
     "build": "ember build --env production --suppress-sizes",
     "build:flags": "RETAIN_FLAGS=true ember build --env production --suppress-sizes",
     "build:typecheck": "tsc -p tsconfig.json --noEmit --pretty false",
-    "changelog": "lerna-changelog",
     "eslint": "eslint . --cache --ext .js,.ts",
     "link:local": "node bin/yarn-link-local",
     "problems": "tsc -p tsconfig.json --noEmit --pretty false",
@@ -78,12 +77,14 @@
     "execa": "^1.0.0",
     "glob": "^7.0.5",
     "js-yaml": "^3.10.0",
-    "lerna-changelog": "^0.8.2",
     "loader.js": "^4.0.10",
     "mkdirp": "^0.5.1",
     "prettier": "^1.19.1",
     "qunit": "^2.9.3",
     "qunit-tap": "^1.5.1",
+    "release-it": "^13.5.1",
+    "release-it-lerna-changelog": "^2.1.2",
+    "release-it-yarn-workspaces": "^1.3.0",
     "rimraf": "^2.7.1",
     "rollup": "^1.31.1",
     "rollup-plugin-sourcemaps": "^0.5.0",
@@ -92,6 +93,9 @@
     "toml": "^3.0.0",
     "typescript": "3.7.5"
   },
+  "publishConfig": {
+    "registry": "https://registry.npmjs.org"
+  },
   "changelog": {
     "repo": "glimmerjs/glimmer-vm",
     "labels": {
@@ -102,8 +106,40 @@
       "internal": ":house: Internal"
     }
   },
+  "release-it": {
+    "hooks": {
+      "before:bump": "yarn build"
+    },
+    "plugins": {
+      "release-it-lerna-changelog": {
+        "infile": "CHANGELOG.md",
+        "launchEditor": true
+      },
+      "release-it-yarn-workspaces": {
+        "workspaces": [
+          "dist/@glimmer/*"
+        ],
+        "additionalManifests": {
+          "dependencyUpdates": [
+            "packages/*/*/package.json"
+          ],
+          "versionUpdates": [
+            "packages/*/*/package.json"
+          ]
+        }
+      }
+    },
+    "git": {
+      "tagName": "v${version}"
+    },
+    "github": {
+      "release": true,
+      "tokenRef": "GITHUB_AUTH"
+    },
+    "npm": false
+  },
   "volta": {
     "node": "10.16.3",
     "yarn": "1.17.3"
   }
-}
+}