chore: migrate fully to Yarn (#3155)

* chore: migrate to Yarn package manager

* chore: bump deps, move `expose-loader` to correct deps section

* fix: remove package from old typescript shim

* feat: use Yarn Plug'n'Play

* chore: keep `node_modules` ignored for people who choose to use npm anyway

* Revert "feat: use Yarn Plug'n'Play"

This reverts commit 9781c8c8d5.

.github/workflows/js.yml

@@ -18,15 +18,15 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ env.NODE_VERSION }}
-          cache: "npm"
-          cache-dependency-path: js/package-lock.json
+          cache: "yarn"
+          cache-dependency-path: js/yarn.lock
 
       - name: Install JS dependencies
-        run: npm ci
+        run: yarn install --immutable
         working-directory: ./js
 
       - name: Check JS formatting
-        run: npm run format-check
+        run: yarn run format-check
         working-directory: ./js
 
   build-prod:
@@ -46,8 +46,8 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ env.NODE_VERSION }}
-          cache: "npm"
-          cache-dependency-path: js/package-lock.json
+          cache: "yarn"
+          cache-dependency-path: js/yarn.lock
 
       # Our action will install npm, cd into `./js`, run `npm run build` and
       # `npm run build-typings`, then commit and upload any changes
@@ -56,7 +56,7 @@ jobs:
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           build_script: build
-          package_manager: npm
+          package_manager: yarn
           typings_script: build-typings
 
   build-test:
@@ -76,8 +76,8 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ env.NODE_VERSION }}
-          cache: "npm"
-          cache-dependency-path: js/package-lock.json
+          cache: "yarn"
+          cache-dependency-path: js/yarn.lock
 
       # Our action will install npm, cd into `./js`, run `npm run build` and
       # `npm run build-typings`, then commit and upload any changes
@@ -86,6 +86,6 @@ jobs:
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           build_script: build
-          package_manager: npm
+          package_manager: yarn
           typings_script: build-typings
           do_not_commit: true