Reset GraphvizUtils#dotVersion

Question

IntelliJ plugin shows a wrong version after user changes graphiz path.

perhaps do this?

public static final void setDotExecutable(String value) {
   String newDotExecutable = value == null ? null : value.trim();
   boolean equals = (dotExecutable == newDotExecutable) || (dotExecutable != null && dotExecutable.equals(newDotExecutable));
   if (!equals) {
      dotVersion = null;
   }
   dotExecutable = newDotExecutable;
}