change update verb for apigee_envgroup to patch (#5047) (#9740)

Signed-off-by: Modular Magician <magic-modules@google.com>

.changelog/5047.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+apigee: fixed update behavior on `google_apigee_envgroup`
+```

google/resource_apigee_envgroup.go

@@ -186,12 +186,6 @@ func resourceApigeeEnvgroupUpdate(d *schema.ResourceData, meta interface{}) erro
 	billingProject := ""
 
 	obj := make(map[string]interface{})
-	nameProp, err := expandApigeeEnvgroupName(d.Get("name"), d, config)
-	if err != nil {
-		return err
-	} else if v, ok := d.GetOkExists("name"); !isEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, nameProp)) {
-		obj["name"] = nameProp
-	}
 	hostnamesProp, err := expandApigeeEnvgroupHostnames(d.Get("hostnames"), d, config)
 	if err != nil {
 		return err
@@ -205,13 +199,24 @@ func resourceApigeeEnvgroupUpdate(d *schema.ResourceData, meta interface{}) erro
 	}
 
 	log.Printf("[DEBUG] Updating Envgroup %q: %#v", d.Id(), obj)
+	updateMask := []string{}
+
+	if d.HasChange("hostnames") {
+		updateMask = append(updateMask, "hostnames")
+	}
+	// updateMask is a URL parameter but not present in the schema, so replaceVars
+	// won't set it
+	url, err = addQueryParams(url, map[string]string{"updateMask": strings.Join(updateMask, ",")})
+	if err != nil {
+		return err
+	}
 
 	// err == nil indicates that the billing_project value was found
 	if bp, err := getBillingProject(d, config); err == nil {
 		billingProject = bp
 	}
 
-	res, err := sendRequestWithTimeout(config, "PUT", billingProject, url, userAgent, obj, d.Timeout(schema.TimeoutUpdate))
+	res, err := sendRequestWithTimeout(config, "PATCH", billingProject, url, userAgent, obj, d.Timeout(schema.TimeoutUpdate))
 
 	if err != nil {
 		return fmt.Errorf("Error updating Envgroup %q: %s", d.Id(), err)