Add support for JSR305.

Common/build.gradle

@@ -23,6 +23,7 @@ minecraft {
 
 dependencies {
      compileOnly group:'org.spongepowered', name:'mixin', version:'0.8.5'
+     implementation group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.1'
 }
 
 processResources {

Fabric/build.gradle

@@ -11,6 +11,7 @@ dependencies {
     mappings loom.officialMojangMappings()
     modImplementation "net.fabricmc:fabric-loader:${fabric_loader_version}"
     modImplementation "net.fabricmc.fabric-api:fabric-api:${fabric_version}"
+    implementation group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.1'
     implementation project(":Common")
 }