Force rebuild of openapi client code each CodexPlugin build.

ProjectPlugins/CodexPluginPrebuild/Program.cs

@@ -4,6 +4,7 @@ using System.Text;
 public static class Program
 {
     private const string OpenApiFile = "../CodexPlugin/openapi.yaml";
+    private const string ClientFile = "../CodexPlugin/obj/openapiClient.cs";
     private const string Search = "<INSERT-OPENAPI-YAML-HASH>";
     private const string TargetFile = "ApiChecker.cs";
 
@@ -11,6 +12,9 @@ public static class Program
     {
         Console.WriteLine("Injecting hash of 'openapi.yaml'...");
 
+        // Force client rebuild by deleting previous artifact.
+        File.Delete(ClientFile);
+
         var hash = CreateHash();
         // This hash is used to verify that the Codex docker image being used is compatible
         // with the openapi.yaml being used by the Codex plugin.