chore: replace lerna with changesets (#1227)

For some time, Lerna would generate garbled changelogs.
Replacing it with changesets helps because changesets lets you specify
which packages to bump intead of trying to figure it out on its own.

* replace lerna prepare with yarn workspaces run
* remove publish command from workspace root else yarn tries (and fails) to publish the root
* move cli example out of packages, it's not meant to be published and it confuses yarn
* update publishing instructions

.changeset/config.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "https://unpkg.com/@changesets/config@1.6.2/schema.json",
+  "changelog": "@changesets/cli/changelog",
+  "commit": false,
+  "linked": [],
+  "access": "public",
+  "baseBranch": "master",
+  "updateInternalDependencies": "patch",
+  "ignore": []
+}

CONTRIBUTING.md

@@ -56,19 +56,28 @@ be edited by hand.
 
 ### Releasing
 
-We use lerna and conventional commits to update the changelog and tag releases.
-To tag a pre-release and generate the changelog, run:
+We use @changesets/cli to update the changelog and tag releases.
+First make sure a changeset exists for every change you want to publish. A changeset is a text file
+with the description of the change and the affected packages.
+To create a changeset run
 
 ```
-yarn lerna version --conventional-commits --conventional-prerelease  --preid rc
+yarn changeset
+``` 
+
+It's best to select the affected packages by hand rather than rely on the tools automatically
+discovering dependencies. For example, if a change affects a plugin `cssnano-preset-default`,
+select the plugin and `cssnano-preset-default` by hand (as well as any other dependent presets).
+To tag a release and generate the changelog, run:
+
+```
+yarn changeset version
 ```
-Use `--conventional-graduate` to generate the tags for a stable release.
 
-To publish the pre-release to npm, run:
+To publish release to npm, run:
 ```
-yarn lerna publish from-package --dist-tag next
+yarn changeset publish from-package
 ```
-To publish a stable release, use `latest` instead of `next`.
 
 ## Are there other ways of contributing?
 

package.json

@@ -5,14 +5,13 @@
     "all-contributors": "all-contributors add",
     "lint": "eslint . --cache --ignore-path .gitignore --ext .js,.mjs",
     "fixlint": "yarn lint -- --fix",
-    "prepare": "lerna run --stream prepare",
+    "prepare": "yarn workspaces run prepare",
     "build:integration": "node ./util/buildFrameworks.mjs",
     "pretest": "yarn lint",
     "test:only": "cross-env BABEL_ENV=test jest",
     "test:coverage": "cross-env BABEL_ENV=test jest --coverage",
     "test": "yarn test:coverage",
-    "deploy": "cd site && GIT_USER=anikethsaha yarn deploy",
-    "publish": "lerna publish"
+    "deploy": "cd site && GIT_USER=anikethsaha yarn deploy"
   },
   "workspaces": [
     "./packages/*"
@@ -24,6 +23,7 @@
     "@babel/cli": "^7.15.7",
     "@babel/core": "^7.15.5",
     "@babel/preset-env": "^7.15.6",
+    "@changesets/cli": "^2.18.0",
     "all-contributors-cli": "^6.20.0",
     "babel-jest": "^27.2.1",
     "babel-plugin-add-module-exports": "^1.0.2",
@@ -42,7 +42,6 @@
     "html-to-text": "^8.0.0",
     "jest": "^27.2.1",
     "jest-junit": "^12.1.0",
-    "lerna": "4.0.0",
     "node-fetch": "^2.6.1",
     "pleeease-filters": "^4.0.0",
     "postcss": "^8.3.0",