Update Codespaces configuration (#60900)

- mark onCreateCommand.sh as executable
- add more regions so users outside of West US can take advantage of prebuilt codespaces
- use v1-stable version, as recommended by docs
- use faster machines for dev productivity

Author: eerhardt

.devcontainer/scripts/onCreateCommand.sh

@@ -9,9 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: github/codespaces-precache@v1.0.1
+      - uses: github/codespaces-precache@v1-stable
         with:
-          regions: WestUs2
-          sku_name: standardLinux32gb
+          regions: WestUs2 EastUs WestEurope
+          sku_name: premiumLinux
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}