Allow to combine %pycached with other macros (e.g. %exclude or %ghost)

Previous implementation allowed for only one argument to be passed to
the %pycached macro, which made it impossible to combine it with other macros.

Current implementation allows to pass other macros as arguments to
%pycached.

Example:

    %pycached %exclude /path/to/foo.py

For macro expansion limitations, the opposite order is not possible.
That is to be documented in the guidelines:
https://pagure.io/packaging-committee/pull-request/986

Added some tests.

Resolves https://bugzilla.redhat.com/show_bug.cgi?id=1838992

Co-authored-by: Marcel Plch <mplch@redhat.com>

macros.python3

@@ -44,7 +44,7 @@
 # This only supports Python 3.5+ and will never work with Python 2.
 # Hence, it has no Python version in the name.
 %pycached() %{lua:
-  path = rpm.expand("%{?1}")
+  path = rpm.expand("%{?*}")
   if (string.sub(path, "-3") ~= ".py") then
     rpm.expand("%{error:%%pycached can only be used with paths explicitly ending with .py}")
   else