Async methods (#155)

* feature: awaitFetch
closes #153

* tweak: param typehint

* feature: await methods, closes #153

* build: php 8.1 compatibility

Author: Greg Bowler

composer.json

@@ -10,7 +10,7 @@
 		"ext-json": "*",
 		"phpgt/async": "^1.0",
 		"phpgt/promise": "^2.2.3",
-		"phpgt/http": "^1.2.1",
+		"phpgt/http": "^1.3",
 		"phpgt/curl": "^3.1.1",
 		"phpgt/json": "^1.2",
 		"phpgt/propfunc": "^1.0"