port update checker to CompletableFuture

src/main/java/com/falsepattern/lib/updates/UpdateCheckException.java

@@ -0,0 +1,22 @@
+package com.falsepattern.lib.updates;
+
+import com.falsepattern.lib.StableAPI;
+
+@StableAPI(since = "0.8.3")
+public class UpdateCheckException extends Exception {
+    public UpdateCheckException(String message) {
+        super(message);
+    }
+
+    public UpdateCheckException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public UpdateCheckException(Throwable cause) {
+        super(cause);
+    }
+
+    protected UpdateCheckException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}