update placeholder

apps/app/src/features/growi-plugin/components/Admin/PluginsExtensionPageContents/PluginInstallerForm.tsx

@@ -51,7 +51,7 @@ export const PluginInstallerForm = (): JSX.Element => {
             className="form-control"
             type="text"
             name="pluginInstallerForm[url]"
-            placeholder="https://github.com/growi/plugins"
+            placeholder="https://github.com/weseek/growi-plugins-example"
             required
           />
           <p className="form-text text-muted">{t('plugins.form.desc_url')}</p>