Build Wasm compiler explorer when deploying docs website (#3928)

Summary:
This ensures that the docs website is always using the latest version of the Relay compiler (`main`) on the website.

*Note*: We can't land this until:

- [x] We're able to upgrade `parking_lot` (at it's current version it is incompatible with `wasm-pack`)
- [ ] Setup a CI job to ensure the compiler playground always builds as part of our internal CI at Meta (otherwise this could easily regress and break deployment of the website)

But got this working and I wanted to save my work somewhere.

Pull Request resolved: #3928

Reviewed By: mofeiZ

Differential Revision:
D46699937

Privacy Context Container: L1125407

Pulled By: captbaritone

fbshipit-source-id: 8dd9bd5f4d843fe047b5b6d792c45c87ecf7d20f

Author: captbaritone

.github/workflows/docusaurus.yml

@@ -11,17 +11,48 @@ on:
       - main
 
 jobs:
+  build-compiler-explorer:
+    name: Build Compiler Explorer
+    runs-on: macos-latest # wasm-pack not working on Ubuntu https://github.com/rustwasm/wasm-pack/issues/781
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: 1.58.0
+          override: true
+      - name: Install wasm-pack
+        run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+      - name: "Build Compiler Playground Wasm NPM package"
+        run: wasm-pack build --target web
+        working-directory: ./compiler/crates/relay-compiler-playground
+      - uses: actions/upload-artifact@v3
+        with:
+          name: compiler-playground-package
+          path: compiler/crates/relay-compiler-playground/pkg/
+
   build-and-deploy:
     runs-on: ubuntu-latest
+    needs: [build-compiler-explorer]
     steps:
       - name: Checkout
         uses: actions/[email protected]
         with:
           persist-credentials: false
 
+      - name: Download Compiler Explorer
+        uses: actions/download-artifact@v2
+        with:
+          name: compiler-playground-package
+          path: tmp/compiler-playground-package
+
+      - name: Link Compiler Explorer
+        run: yarn link
+        working-directory: tmp/compiler-playground-package
+
       - name: Install and Build
         run: |
           yarn
+          yarn link relay-compiler-playground
           yarn build
         working-directory: website/