jsonschema: update validator to the latest draft

The JSON Schema "draft 7" is now old and the latest is
"2020-12".  Switch the validator object we use to be the
latest version.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I90a0d9b8669bade600ca3d48041f31727e410e14
diff --git a/scripts/validate_configs.py b/scripts/validate_configs.py
index 3afd335..ae5fb19 100755
--- a/scripts/validate_configs.py
+++ b/scripts/validate_configs.py
@@ -134,7 +134,7 @@
             )
             sys.exit(2)
 
-    spec = jsonschema.Draft7Validator
+    spec = jsonschema.Draft202012Validator
     spec.check_schema(schema)
     base_uri = "file://{}/".format(
         os.path.split(os.path.realpath(schema_file))[0]