ci: run tests with libyang v3.13.6

Set upstream libyang branch to the latest v3 release rather than the default of
master.

Signed-off-by: Christian Hopps <[email protected]>

Author: choppsv1

tox.ini

@@ -14,6 +14,8 @@ install_command = {toxinidir}/tox-install.sh {envdir} {opts} {packages}
 allowlist_externals =
 	{toxinidir}/tox-install.sh
 commands = python -Wd -m unittest discover -c
+setenv =
+	LIBYANG_BRANCH=v3.13.6 # On v3 branch test using last libyang v3 release
 
 [testenv:lydevel]
 setenv =