[build] fix 0.1.0-alpha3 in global.json

a7370d64 broke the build, this should fix.
2021-07-26 16:37:57 -05:00 · 2021-07-26 16:37:57 -05:00 · ed849228ed
--- a/global.json
+++ b/global.json
@ -4,6 +4,6 @@
  },
  "msbuild-sdks": {
    "Microsoft.Build.NoTargets": "2.0.1",
-    "Xamarin.Legacy.Sdk": "0.1.0-alpha2"
+    "Xamarin.Legacy.Sdk": "0.1.0-alpha3"
  }
 }