Use forgegradle 2.2 for 1.11

:fixMcSources fails on a clean cache when decompiling 1.11.2 with
forgegradle 2.3. We should stick to v2.2 until we use 1.12

Author: LeafHacker

build.gradle

@@ -15,7 +15,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'net.minecraftforge.gradle:ForgeGradle:2.3-SNAPSHOT'
+        classpath 'net.minecraftforge.gradle:ForgeGradle:2.2-SNAPSHOT'
         classpath 'org.spongepowered:mixingradle:0.4-SNAPSHOT'
         classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.0'
     }