Update src/main/java/org/kohsuke/github/GHRateLimit.java

Author: bitwiseman

src/main/java/org/kohsuke/github/GHRateLimit.java

@@ -345,7 +345,7 @@ public static class UnknownLimitRecord extends Record {
         private static final UnknownLimitRecord DEFAULT = new UnknownLimitRecord(Long.MIN_VALUE);
 
         // The starting current UnknownLimitRecord is an expired record.
-        private static AtomicReference<UnknownLimitRecord> current = new AtomicReference<>(DEFAULT);
+        private static final AtomicReference<UnknownLimitRecord> current = new AtomicReference<>(DEFAULT);
 
         /**
          * Create a new unknown record that resets at the specified time.