apply fix from source issues

Azure-Samples#2

Author: VAO11

.github/workflows/main_funcappvao.yml

@@ -11,7 +11,7 @@ on:
 
 env:
   AZURE_FUNCTIONAPP_PACKAGE_PATH: '.' # set this to the path to your web app project, defaults to the repository root
-  DOTNET_VERSION: 'v4.0' # set this to the dotnet version to use
+  DOTNET_VERSION: 'v3.1.x' # set this to the dotnet version to use
 
 jobs:
   build-and-deploy: