Remove only absolute import. (#331)

Everything seem to be using relative import except this line (and the
tests and scripts). Be consistent.

Author: Carreau

jupyter_core/paths.py

@@ -21,7 +21,7 @@
 
 import platformdirs
 
-from jupyter_core.utils import deprecation
+from .utils import deprecation
 
 pjoin = os.path.join