debian/control: Remove cython3-legacy option, policykit-1 dep.

- Latest grpcio can build using regular cython3.
- policykit's gettext definition file is kept in
  libpolkit-gobject-1-dev now, not policykit-1.

Author: mtwebster

debian/control

@@ -4,13 +4,12 @@ Priority: optional
 Maintainer: Linux Mint <[email protected]>
 Build-Depends:
  debhelper-compat (= 12),
- cython3-legacy | cython3,
+ cython3,
  curl,
  dh-python,
  libpolkit-gobject-1-dev,
  meson (>= 0.45.0),
  pkg-config,
- policykit-1,
  python3-dev,
  python3-setuptools,
  gobject-introspection