Remove global.json because .403 became suddenly unavailable

.circleci/config.yml

@@ -18,7 +18,6 @@ jobs:
             sudo apt-get update
             sudo apt-get install dotnet-sdk-2.1
             dotnet --info
-            rm global.json
             dotnet build /p:TreatWarningsAsErrors=true
             cd BTCPayServer.Tests
             dotnet test --filter Fast=Fast

global.json

@@ -1,5 +0,0 @@
-{
-  "sdk": {
-    "version": "2.1.403"
-  }
-}