change python version to 3.5.6

.gitlab-ci.yml

@@ -18,7 +18,7 @@ westpy_build:
    - apt-get -qq install zlib1g-dev > /dev/null
    - apt-get -qq install libssl-dev > /dev/null
    - cd /opt
-   - export PY_VERSION="3.5.4"
+   - export PY_VERSION="3.5.6"
    - wget https://www.python.org/ftp/python/$PY_VERSION/Python-$PY_VERSION.tgz
    - tar -xzf Python-$PY_VERSION.tgz
    - cd Python-$PY_VERSION