Merge pull request php-vcr#319 from php-vcr/1.5-allow-symfony-yaml-5

Allow using symfony/yaml ^5.0

Author: JeroenVanOort

composer.json

@@ -21,7 +21,7 @@
  "php": ">=7.2",
  "ext-curl": "*",
  "beberlei/assert": "^3.2.5",
- "symfony/yaml": "~2.1|^3.0|^4.0",
+ "symfony/yaml": "~2.1|^3.0|^4.0|^5.0",
  "symfony/event-dispatcher": "^2.4|^3.0|^4.0|^5.0"
  },