.gitlab-ci.yml: add missing python-avro test

Commit 9fa2add810c (support/testing: add test for python-avro) added a
test for python-avro but failed to update .gitlab-ci.yml. Do that now.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

.gitlab-ci.yml

@@ -438,6 +438,7 @@ tests.package.test_python_autobahn.TestPythonPy2Autobahn: { extends: .runtime_te
 tests.package.test_python_autobahn.TestPythonPy3Autobahn: { extends: .runtime_test }
 tests.package.test_python_automat.TestPythonPy2Automat: { extends: .runtime_test }
 tests.package.test_python_automat.TestPythonPy3Automat: { extends: .runtime_test }
+tests.package.test_python_avro.TestPythonAvro: { extends: .runtime_test }
 tests.package.test_python_bitstring.TestPythonPy2Bitstring: { extends: .runtime_test }
 tests.package.test_python_bitstring.TestPythonPy3Bitstring: { extends: .runtime_test }
 tests.package.test_python_cbor.TestPythonPy2Cbor: { extends: .runtime_test }