No. Even though you make a death saving throw on your turn, it is not an action. The Incapacitated condition in the Player’s Handbook states that "An incapacitated creature can’t take actions or reactions,” so it’s technically impossible for death saves to be actions. This does mean, therefore, that if you roll a 20 and jump back up to 1 hit point, you can take an action - although you begin your turn prone and must spend movement to stand up.