Hybridisation is strictly related to geometry. Moreover, for second row elements, like nitrogen, hybrid orbitals are a mixture of s and p character only.
Provided nitrogen geometry in pyridine is trigonal planar (due to VSEPR theory) it uses three hybrid orbitals with the same triangular planar shape for the two sigma bonds (with adjacent carbons) and for the lone pair that is directed outward on the ring plane.
These three are sp² orbitals, formed by the three 2s, 2px and 2py orbitals. The remaining 2pz orbital (unhybridised) is perpendicular to the ring and shares one electron to the aromatic pi sextet.