[CMake] keep the python module as a folder for now

ref
https://github.com/stack-of-tasks/tsid/pull/72#issuecomment-597082552
14 jobs for master in 16 minutes and 19 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Test
passed doc-coverage #78798

00:16:17

35.0%
failed format #78799
allowed to fail

00:00:17

passed robotpkg-py-tsid-16.04-debug #78787

00:09:52

passed robotpkg-py-tsid-16.04-release #78786

00:08:47

passed robotpkg-py-tsid-18.04-debug #78791

00:11:18

passed robotpkg-py-tsid-18.04-release #78790

00:11:04

passed robotpkg-py-tsid-py3-16.04-debug #78789

00:09:52

passed robotpkg-py-tsid-py3-16.04-release #78788

00:08:53

passed robotpkg-py-tsid-py3-18.04-debug #78793

00:11:34

passed robotpkg-py-tsid-py3-18.04-release #78792

00:11:04

passed robotpkg-tsid-16.04-debug #78795

00:06:19

passed robotpkg-tsid-16.04-release #78794

00:03:47

passed robotpkg-tsid-18.04-debug #78797

00:05:30

passed robotpkg-tsid-18.04-release #78796

00:04:00

 
Name Stage Failure
failed
format Test
+  const Model& model() const;
+ Model& model();
+
+ void computeAllTerms(Data& data, const Vector& q, const Vector& v) const;
+
+ const Vector& rotor_inertias() const;
+ const Vector&
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1