Fatal error after update to 8.x-3.0-rc2

Hello,

I have the following fatal error after updating to 8.x-3.0-rc2.

I will investigate tomorrow.

Thanks for any help.

Drupal\Component\Plugin\Exception\PluginException: Plugin (schema) instance class "Drupal\bootstrap\Plugin\Setting\Update" does not exist. in Drupal\Component\Plugin\Factory\DefaultFactory::getPluginClass() (line 97 of core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php).

Drupal\Core\Plugin\Factory\ContainerFactory->createInstance('schema', Array) (Line: 84)
Drupal\Component\Plugin\PluginManagerBase->createInstance('schema', Array) (Line: 88)
Drupal\bootstrap\Plugin\PluginManager->createInstance('schema') (Line: 447)
Drupal\bootstrap\Theme->getSettingPlugins() (Line: 59)
Drupal\bootstrap\ThemeSettings->__construct(Object, Object) (Line: 577)
Drupal\bootstrap\Theme->settings() (Line: 433)
Drupal\bootstrap\Theme->getSetting('schemas') (Line: 118)
Drupal\bootstrap\Theme->__construct(Object, Object) (Line: 452)
Drupal\bootstrap\Bootstrap::getTheme('bootstrap', Object) (Line: 273)
Drupal\bootstrap\Theme->getAncestry() (Line: 60)
Drupal\bootstrap\Plugin\PluginManager->__construct(Object, 'Plugin/Setting', 'Drupal\bootstrap\Plugin\Setting\SettingInterface', 'Drupal\bootstrap\Annotation\BootstrapSetting') (Line: 26)
Drupal\bootstrap\Plugin\SettingManager->__construct(Object) (Line: 445)
Drupal\bootstrap\Theme->getSettingPlugins() (Line: 59)
Drupal\bootstrap\ThemeSettings->__construct(Object, Object) (Line: 577)
Drupal\bootstrap\Theme->settings() (Line: 433)
Drupal\bootstrap\Theme->getSetting('schemas') (Line: 118)
Drupal\bootstrap\Theme->__construct(Object, Object) (Line: 452)
Drupal\bootstrap\Bootstrap::getTheme() (Line: 987)
Drupal\bootstrap\Bootstrap::initialize() (Line: 30)
include_once('/project/www/themes/contrib/bootstrap/bootstrap.theme') (Line: 140)
Drupal\Core\Extension\Extension->load() (Line: 35)
twig_init(Object)
call_user_func('twig_init', Object) (Line: 137)
Drupal\Core\Theme\ThemeInitialization->loadActiveTheme(Object) (Line: 67)
Drupal\Core\Theme\ThemeInitialization->initTheme('drupalcampfr_theme') (Line: 406)
Drupal\Core\Theme\ThemeManager->initTheme(Object) (Line: 96)
Drupal\Core\Theme\ThemeManager->getActiveTheme() (Line: 74)
Drupal\Core\Render\ElementInfoManager->getInfo('markup') (Line: 298)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 574)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
call_user_func(Array, Object, 'kernel.view', Object) (Line: 61)
Symfony\Component\EventDispatcher\Debug\WrappedListener->__invoke(Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 140)
Symfony\Component\EventDispatcher\Debug\TraceableEventDispatcher->dispatch('kernel.view', Object) (Line: 149)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 64)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 206)
Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 120)
Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 74)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 43)
Drupal\webprofiler\StackMiddleware\WebprofilerMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 628)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)