Fix: ConcurrentModificationException

HMCLCore/src/main/java/org/jackhuang/hmcl/download/optifine/OptiFineBMCLVersionList.java

@@ -56,6 +56,9 @@ public final class OptiFineBMCLVersionList extends VersionList<OptiFineRemoteVer
 
             @Override
             public void execute() {
+                lock.writeLock().lock();
+
+                try {
                     versions.clear();
                     Set<String> duplicates = new HashSet<>();
                     List<OptiFineVersion> root = JsonUtils.GSON.fromJson(task.getResult(), new TypeToken<List<OptiFineVersion>>() {
@@ -74,6 +77,9 @@ public final class OptiFineBMCLVersionList extends VersionList<OptiFineRemoteVer
                         String gameVersion = VersionNumber.normalize(element.getGameVersion());
                         versions.put(gameVersion, new OptiFineRemoteVersion(gameVersion, version, mirror, isPre));
                     }
+                } finally {
+                    lock.writeLock().unlock();
+                }
             }
         };
     }