TE-8537 Added PHP 8 Travis support (#1904)

TE-8537 PHP8 (future check) in CI

phpstan.neon

@@ -15,3 +15,5 @@ parameters:
         - '#Instantiated class .+NativePasswordEncoder not found.#'
         - '#Comparison operation "<" between [1-9] and 3 is always (true|false).#'
         - '#Else branch is unreachable because previous condition is always true.#'
+    excludePaths:
+        - %rootDir%/../../../vendor/spryker/spryker-shop/Bundles/ShopApplication/src/SprykerShop/Yves/ShopApplication/Plugin/AbstractTwigExtensionPlugin.php

src/SprykerShop/Yves/ShopApplication/Bootstrap/YvesBootstrap.php

@@ -38,8 +38,10 @@ public function boot(): ApplicationInterface
      *
      * @return \Spryker\Yves\Kernel\Container
      */
-    protected function provideExternalDependencies(AbstractBundleDependencyProvider $dependencyProvider, Container $container)
-    {
+    protected function provideExternalDependencies(
+        AbstractBundleDependencyProvider $dependencyProvider,
+        Container $container
+    ): Container {
         $dependencyProvider->provideDependencies($container);
 
         return $container;
@@ -49,10 +51,12 @@ protected function provideExternalDependencies(AbstractBundleDependencyProvider
      * @param \Spryker\Yves\Kernel\Dependency\Injector\DependencyInjector $dependencyInjector
      * @param \Spryker\Yves\Kernel\Container $container
      *
-     * @return \Spryker\Shared\Kernel\ContainerInterface|\Spryker\Zed\Kernel\Container
+     * @return \Spryker\Yves\Kernel\Container
      */
-    protected function injectExternalDependencies(DependencyInjector $dependencyInjector, Container $container)
-    {
+    protected function injectExternalDependencies(
+        DependencyInjector $dependencyInjector,
+        Container $container
+    ): Container {
         $container = $dependencyInjector->inject($container);
 
         return $container;