Fix VB check on Velocity/Sponge

sponge/src/main/java/us/myles/ViaVersion/SpongePlugin.java

@@ -75,7 +75,7 @@ public class SpongePlugin implements ViaPlatform<Player> {
 
     @Listener
     public void onServerStart(GameAboutToStartServerEvent event) {
-        if (game.getPluginManager().getPlugin("ViaBackwards").isPresent()) {
+        if (game.getPluginManager().getPlugin("viabackwards").isPresent()) {
             MappingDataLoader.enableMappingsCache();
         }
 

velocity/src/main/java/us/myles/ViaVersion/VelocityPlugin.java

@@ -80,7 +80,7 @@ public class VelocityPlugin implements ViaPlatform<Player> {
                 .loader(new VelocityViaLoader())
                 .injector(new VelocityViaInjector()).build());
 
-        if (proxy.getPluginManager().getPlugin("ViaBackwards").isPresent()) {
+        if (proxy.getPluginManager().getPlugin("viabackwards").isPresent()) {
             MappingDataLoader.enableMappingsCache();
         }
     }