Remove deprecated python3-subprocess from the RDEPENDS

The python3-subprocess package was merged into core as part of the
json manifest migration

Signed-off-by: Derek Straka <derek@asterius.io>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-python/recipes-devtools/python/python-attrs.inc

@@ -10,5 +10,4 @@ inherit pypi
 
 RDEPENDS_${PN}_class-target += " \
     ${PYTHON_PN}-ctypes \
-    ${PYTHON_PN}-subprocess \
 "