Merge pull request #15 from localheinz/feature/source

Enhancement: Add link to source to `composer.json`

Author: Jean85

composer.json

@@ -18,6 +18,9 @@
             "homepage": "https://www.php-fig.org/"
         }
     ],
+    "support": {
+        "source": "https://github.com/php-fig/http-factory"
+    },
     "require": {
         "php": ">=7.0.0",
         "psr/http-message": "^1.0 || ^2.0"