meta-python: remove obsolete dependencies on python3-six

These recipes no longer use six, so remove the dependency.

The list of recipes that still use six is a somewhat useful proxy for
packages that are no longer maintained...

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Khem Raj <khem.raj@oss.qualcomm.com>

meta-python/recipes-devtools/python/python3-pynacl_1.6.2.bb

@@ -23,7 +23,6 @@ do_install:prepend() {
 }
 
 RDEPENDS:${PN} = "\
-    python3-six \
     python3-cffi \
     libsodium \
 "