Fix inconsistent repository definitions.

Common/build.gradle

@@ -5,10 +5,6 @@ plugins {
 
 archivesBaseName = "${mod_name}-common-${minecraft_version}"
 
-repositories {
-    mavenCentral()
-}
-
 minecraft {
     version(minecraft_version)
     runs {   

Fabric/build.gradle

@@ -6,9 +6,6 @@ plugins {
 
 archivesBaseName = "${mod_name}-fabric-${minecraft_version}"
 
-repositories {
-}
-
 dependencies {
     minecraft "com.mojang:minecraft:${minecraft_version}"
     mappings loom.officialMojangMappings()

Forge/build.gradle

@@ -66,9 +66,6 @@ minecraft {
 
 sourceSets.main.resources { srcDir 'src/generated/resources' }
 
-repositories {
-}
-
 dependencies {
     minecraft "net.minecraftforge:forge:${minecraft_version}-${forge_version}"
     compileOnly project(":Common")

build.gradle

@@ -22,4 +22,19 @@ subprojects {
             ])
         }
     }
+    
+    repositories {
+
+        mavenCentral()
+
+        maven {
+            name = 'Sponge / Mixin'
+            url = 'https://repo.spongepowered.org/repository/maven-public/'
+        }
+
+        maven {
+            name = 'BlameJared Maven (CrT / Bookshelf)'
+            url = 'https://maven.blamejared.com'
+        }
+    }
 }