Configure editorconfig to use explicit types

.editorconfig

@@ -135,9 +135,9 @@ csharp_style_prefer_null_check_over_type_check = true:warning
 # https://docs.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/language-rules#c-style-rules
 [*.{cs,csx,cake}]
 # 'var' preferences
-csharp_style_var_for_built_in_types = false:warning
-csharp_style_var_when_type_is_apparent = false:warning
-csharp_style_var_elsewhere = false:warning
+csharp_style_var_for_built_in_types = false:error
+csharp_style_var_when_type_is_apparent = false:error
+csharp_style_var_elsewhere = false:error
 # Expression-bodied members
 csharp_style_expression_bodied_methods = true:warning
 csharp_style_expression_bodied_constructors = true:warning