Relax psr/log requirement so projects can use a newer version

Author: pprkut

composer.json

@@ -30,7 +30,7 @@
 	"require": {
 		"php": ">=5.6.0",
 		"colinmollenhour/credis": "~1.7",
-		"psr/log": "~1.0"
+		"psr/log": ">=1.1.0"
 	},
 	"suggest": {
 		"ext-pcntl": "REQUIRED for forking processes on platforms that support it (so anything but Windows).",