Update composer.json

Author: GrahamCampbell

composer.json

@@ -28,6 +28,7 @@
 		"php-http/discovery": "^1.2",
 		"php-http/httplug": "^1.1 || ^2.0",
 		"php-http/multipart-stream-builder": "^1.0",
+		"psr/http-message": "^1.0",
 		"symfony/options-resolver": "^2.6 || ^3.0 || ^4.0 || ^5.0"
 	},
 	"require-dev": {
@@ -41,10 +42,5 @@
 	},
 	"autoload-dev": {
 		"psr-4": { "Gitlab\\Tests\\": "test/Gitlab/Tests/" }
-	},
-	"extra": {
-		"branch-alias": {
-			"dev-master": "9.16-dev"
-		}
 	}
 }