azure-pipelines: add trigger for libiio-v0 branch

libiio-v0 is the branch for old libiio API. There is also v0.25 release
that has associated all archives. But we found bugs on release and the
fixes got pushed into libiio-v0 branch. So we need to keep the CI for
old API active. The CI uses azure-pipelines.yml from libiio-v0 branch,
meaning that the single impact on master is just on triggering.

Signed-off-by: Stefan Raus <[email protected]>
(cherry picked from commit 53765a1)

Author: SRaus

azure-pipelines.yml

@@ -7,6 +7,7 @@ trigger:
     - main
     - master
     - next_stable
+    - libiio-v0
     - staging/*
     - 20*
   tags: