Replace git.openstack.org URLs with opendev.org URLs

Change-Id: I2f13a051cb74dcb097715b825eecbea7e0b9fb06
diff --git a/tox.ini b/tox.ini
index 24f9f4b..7490e90 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@
 usedevelop = True
 install_command = pip install {opts} {packages}
 deps =
-       -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
+       -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 setenv =