fix: add gen:types-csharp target for CI

The C# types are handwritten (not auto-generated) so the target
just outputs a message and exits successfully like Ruby.

Amp-Thread-ID: https://ampcode.com/threads/T-019baef5-42c2-76ac-9db4-4be0c6931088

Author: lox

internal/gen/main.go

@@ -23,6 +23,8 @@ func generateTypes(outDir, language string) error {
 		return generatePythonTypes(generator, outDir)
 	case "go":
 		return generateGoTypes(generator, outDir)
+	case "csharp":
+		return generateCSharpTypes(generator, outDir)
 	}
 
 	return nil

project.json

@@ -68,6 +68,16 @@
                 "parallel": false
             }
         },
+        "gen:types-csharp": {
+            "executor": "nx:run-commands",
+            "options": {
+                "commands": [
+                    "echo 'C# type generation not implemented (types are handwritten)'",
+                    "exit 0"
+                ],
+                "parallel": false
+            }
+        },
         "gen:types-go": {
             "executor": "nx:run-commands",
             "options": {