timespan code gen

Author: balassit

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AspNetServerCodegen.java

@@ -327,7 +327,7 @@ private void addCentralizedPackageManagementOption(){
     @Override
     protected Set<String> getNullableTypes() {
         return new HashSet<>(Arrays.asList("decimal", "bool", "int", "uint", "long", "ulong", "float", "double",
-                "DateTime", "DateOnly", "DateTimeOffset", "Guid"));
+                "DateTime", "DateOnly", "DateTimeOffset", "TimeSpan", "Guid"));
     }
 
     @Override

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpFunctionsServerCodegen.java

@@ -260,7 +260,7 @@ public CSharpFunctionsServerCodegen() {
     @Override
     protected Set<String> getNullableTypes() {
         return new HashSet<>(Arrays.asList("decimal", "bool", "int", "uint", "long", "ulong", "float", "double",
-            "DateTime", "DateTimeOffset", "Guid"));
+            "DateTime", "DateTimeOffset", "TimeSpan", "Guid"));
     }
 
     @Override

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpReducedClientCodegen.java

@@ -306,7 +306,7 @@ public CSharpReducedClientCodegen() {
     @Override
     protected Set<String> getNullableTypes() {
         return new HashSet<>(Arrays.asList("decimal", "bool", "int", "uint", "long", "ulong", "float", "double",
-            "DateTime", "DateTimeOffset", "Guid"));
+            "DateTime", "DateTimeOffset", "TimeSpan", "Guid"));
     }
 
     @Override