The End of Dragons by Mark Stay

To Survive, They Must Kill The Last of Her Kind.
The Lapis Moon is gone. Magic is dying. The world has moved on.
Mages, however, are an endangered species. Sander Bree is scraping a living as a mage for hire, Rosheen Katell is in hiding with her brother Oskar. All mages are outlawed, exiled, dodging assassins and the wrath of Archbishop Yorath Pasco who would gladly have them skewered in public.

Then a dragon attacks a small fishing village on the Parthalan coast. Dragons aren’t supposed to exist in these enlightened times, and so the Archbishop suggests a deal: if Sander and Rosheen use their magic to slay the dragon without fuss then their slates will be wiped clean. Of course, they encounter personal betrayals, political backstabbing, criminal shenanigans and a bloody great dragon in a rollicking adventure that will keep you on the edge of your seat.