fix(docs): Use correct "configuration" property in plugin docs

docs/content/docs/plugins/plugin-examples.md

@@ -20,7 +20,7 @@ This example shows how to modify the VendureConfig, in this case by adding a cus
 import { VendurePlugin } from '@vendure/core';
 
 @VendurePlugin({
-  configure: config => {
+  configuration: config => {
     config.customFields.Product.push({
       name: 'rating',
       type: 'float',
@@ -342,7 +342,7 @@ import { ProductVideoResolver } from './product-video.resolver'
     `,
     resolvers: [ProductVideoResolver]
   },
-  configure: config => {
+  configuration: config => {
     config.customFields.Product.push({
       name: 'videoUrl',
       type: 'string',

packages/core/src/plugin/plugin-utils.ts

@@ -16,7 +16,7 @@ import { Logger, RuntimeVendureConfig, VendureConfig } from '../config';
  * // running some service which we want to access via the `/my-plugin/`
  * // route of the main Vendure server.
  * \@VendurePlugin({
- *   configure: (config: Required<VendureConfig>) => {
+ *   configuration: (config: Required<VendureConfig>) => {
  *       config.apiOptions.middleware.push({
  *           handler: createProxyHandler({
  *               label: 'Admin UI',