Fixed adding apiVersionSetId to initial template (#362)

Co-authored-by: RupengLiu <rliu1211@terpmail.umd.edu>

Author: jjinxn

src/APIM_ARMTemplate/apimtemplate/Creator/TemplateCreators/APITemplateCreator.cs

@@ -199,6 +199,12 @@ public async Task<APITemplateResource> CreateAPITemplateResourceAsync(APIConfig
                         // open api spec is local yaml file
                         format = "openapi";
                     }
+                }
+				// set the version set id
+                if (api.apiVersionSetId != null)
+                {
+                    // point to the supplied version set if the apiVersionSetId is provided
+                    apiTemplateResource.properties.apiVersionSetId = $"[resourceId('Microsoft.ApiManagement/service/apiVersionSets', parameters('{ParameterNames.ApimServiceName}'), '{api.apiVersionSetId}')]";
                 }
                 apiTemplateResource.properties.format = format;
                 apiTemplateResource.properties.value = value;