Release branch C++ depends on release branch in C

Signed-off-by: Erik Boasson <[email protected]>

.azure/templates/build-test.yml

@@ -104,7 +104,7 @@ steps:
   - bash: |
       set -e -x
       git clone --single-branch \
-                --branch "${CYCLONEDDS_BRANCH:-master}" \
+                --branch "${CYCLONEDDS_BRANCH:-releases/0.10.x}" \
                 "${CYCLONEDDS_REPOSITORY:-https://github.com/eclipse-cyclonedds/cyclonedds.git}" \
                 cyclonedds
       mkdir cyclonedds/build