Merge branch '4.3'

* 4.3:
  [Routing] Fixed unexpected 404 NoConfigurationException
  [DI] Removes number of elements information in debug mode
  [Contracts] Simplify implementation declarations
  Update PR template for 4.3
  [Intl] Add FallbackTrait for data generation
  [Console] Commands with an alias should not be recognized as ambiguous
  clarify the possible class/interface of the cache

composer.json

@@ -16,7 +16,7 @@
     ],
     "provide": {
         "psr/http-client-implementation": "1.0",
-        "symfony/http-client-contracts-implementation": "1.1"
+        "symfony/http-client-implementation": "1.1"
     },
     "require": {
         "php": "^7.1.3",