meson: track python script dependency

Suggested-by: Andres Gomez <agomez@igalia.com>
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

src/amd/vulkan/meson.build

@@ -24,6 +24,7 @@ radv_entrypoints = custom_target(
   output : ['radv_entrypoints.h', 'radv_entrypoints.c'],
   command : [prog_python2, '@INPUT0@', '--xml', '@INPUT1@',
              '--outdir', meson.current_build_dir()],
+  depend_files : files('radv_extensions.py'),
 )
 
 radv_extensions = custom_target(