README.md: Update the repo link after oniro migration

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

README.md

@@ -30,7 +30,7 @@ Please follow the recommended setup procedures of your OE distribution.
 
 Contributions to this layer are to be handled as merge requests in the Gitlab
 instance where the layer is hosted:
-https://git.ostc-eu.org/OSTC/ASOS/meta-python-mixin.
+https://booting.oniroproject.org/distro/meta-python-mixin.
 
 ## Maintenance