Increase maintainer digit limit to 16.

src/main/java/com/glodblock/github/client/gui/GuiLevelMaintainer.java

@@ -538,7 +538,7 @@ public Widget(FCGuiTextField textField, String tooltip, int idx, Action action)
             this.textField = textField;
             this.textField.setEnableBackgroundDrawing(false);
             this.textField.setText("0");
-            this.textField.setMaxStringLength(10); // this length is enough to useful
+            this.textField.setMaxStringLength(16); // this length is enough to be useful
             this.idx = idx;
             this.action = action;
             this.tooltip = tooltip;