Update MixinBooter version (#40)

Author: ALongStringOfNumbers

build.gradle

@@ -368,10 +368,6 @@ repositories {
         }
     }
     if (usesMixins.toBoolean() || forceEnableMixins.toBoolean()) {
-        maven {
-            name 'Sponge Maven'
-            url 'https://repo.spongepowered.org/maven'
-        }
         // need to add this here even if we did not above
         if (!includeWellKnownRepositories.toBoolean()) {
             maven {
@@ -401,8 +397,8 @@ configurations {
 
 dependencies {
     if (usesMixins.toBoolean() || forceEnableMixins.toBoolean()) {
-        implementation 'zone.rong:mixinbooter:7.0'
-        String mixin = 'org.spongepowered:mixin:0.8.3'
+        implementation 'zone.rong:mixinbooter:8.3'
+        String mixin = 'zone.rong:mixinbooter:8.3'
         if (usesMixins.toBoolean()) {
             mixin = modUtils.enableMixins(mixin, "mixins.${modId}.refmap.json")
         }