Update Pyodide to 0.21.0

Author: messense

.github/workflows/ci.yml

@@ -412,10 +412,10 @@ jobs:
         with:
           node-version: 18
       - run: |
-          PYODIDE_VERSION=0.21.0-alpha.3
+          PYODIDE_VERSION=0.21.0
 
           cd emscripten
-          npm i [email protected]-alpha.3 prettier
+          npm i [email protected] prettier
           cd node_modules/pyodide/
           node ../prettier/bin-prettier.js -w pyodide.asm.js
           EMSCRIPTEN_VERSION=$(node -p "require('./repodata.json').info.platform.split('_').slice(1).join('.')")