python3-dt-schema: remove recipe

Since 2021-11-23 this is on oe-core:
d56fcb5806 ("python: introduce python3-dtschema")

The recipe in oe-core is named python3-dtschema (without dash between
'dt' and 'schema'). It points to the correct GIT repository and uses a
much more recent version.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Trevor Gamblin <trevor.gamblin@windriver.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-python/recipes-core/packagegroups/packagegroup-meta-python.bb

@@ -113,7 +113,6 @@ RDEPENDS:packagegroup-meta-python3 = "\
     python3-docopt \
     python3-docutils \
     python3-dominate \
-    python3-dt-schema \
     python3-dynamic-dispatch \
     python3-ecdsa \
     python3-editor \