message: Update emscripten in Google Actions.
  This now matches what is already specified in BUILDING.md
diff: @@ -9,7 +9,7 @@ export PATH="$PWD:$PATH"
  # npm install -g typescript
  # Install emscripten.
  -curl -L https://github.com/emscripten-core/emsdk/archive/1.39.19.zip > emsdk.zip
  +curl -L https://github.com/emscripten-core/emsdk/archive/2.0.12.zip > emsdk.zip
  unzip emsdk.zip ; mv emsdk-* emsdk ; cd emsdk
  ./emsdk install latest
  ./emsdk activate latest
  