File use-python-3.6.patch of Package libratbag

--- a/meson.build
+++ b/meson.build
@@ -496,7 +496,7 @@ configure_file(input : 'dbus/org.freedes
 # doesn't exist and isn't logged as "not found".
 dep_python3 = dependency('', required : false)
 pymod = import('python')
-py3 = pymod.find_installation()
+py3 = pymod.find_installation('python3.6')
 if meson.version().version_compare('>= 0.53.0')
   dep_python3 = py3.dependency(embed : true)
 endif