src/meson.build: Bumps libhandy version to 1.5.0
HdyStyleManager only exists in libhandy 1.5.0 so it doesn't make sense to require 1.0.0 since it doesn't build with 1.0.0.
Fixes #757 (closed)
HdyStyleManager only exists in libhandy 1.5.0 so it doesn't make sense to require 1.0.0 since it doesn't build with 1.0.0.
Fixes #757 (closed)