In this situation, have you just completed a passing manoeuvre?

In this situation, you are passing a heavy goods vehicle coming from the opposite direction, which is the definition of a passing manoeuvre (passing oncoming traffic). According to Art. 2 pt. 27 of the Road Traffic Act, "omijanie" (passing stationary objects) consists of passing a non-moving vehicle, traffic participant or obstacle; therefore, in this case, the answer is negative.