Pin pylint version to 2.17.7 in tox.ini

Change-Id: I765081c918c8e47b92a3c3c50247a0f98d482d2a
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

releasenotes/notes/pin_pylint_version-6c6133428fbca887.yaml

+#######################################################################################
+# Copyright ETSI Contributors and Others.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#######################################################################################
+---
+other:
+  - |
+    Pin pylint version ito 2.17.7 so that pylint tests do not present version
+    with the new version 3.0.0, which has still some bugs.
+

tox.ini

@@ -172,7 +172,7 @@ commands =
 deps =  {[testenv]deps}
         -r{toxinidir}/requirements-dev.txt
         -r{toxinidir}/requirements-test.txt
-        pylint
+        pylint==2.17.7
 skip_install = true
 commands =
         pylint -E NG-RO/osm_ng_ro --disable=E1101