refactor: switch to NPM workspaces

The `lerna bootstrap` command is deprecated[1]
and resulted in a very weird CI failure (dequelabs#685).

This commit switches the repository to instead use
NPM workspaces.[2]

[1]: lerna/lerna#3410
[2]: https://docs.npmjs.com/cli/v7/using-npm/workspaces

.circleci/config.yml

@@ -65,7 +65,6 @@ jobs:
           key: v2-root-npm-{{ checksum "package-lock.json" }}
           paths:
             - node_modules
-      - run: npm run bootstrap -- --ci
       - save_cache:
           key: v2-cli-npm-{{ checksum "packages/cli/package-lock.json" }}
           paths:
@@ -210,8 +209,7 @@ jobs:
       - run: npm install -g node@14 --force
       - checkout
       - restore_dependency_cache
-      - run: npm install
-      - run: npm run bootstrap -- --ci
+      - run: npm ci
       - run: npm run build --prefix=packages/playwright
       - run: npm run coverage --prefix=packages/playwright