As was suggested i created special docker image that setup default locale to

en_US.UTF-8.

--HG--
branch : develop

bitbucket-pipelines.yml

@@ -1,4 +1,4 @@
-image: gcc
+image: dismine/docker-valentina
 pipelines:
   default:
     - step:
@@ -12,8 +12,6 @@ pipelines:
             - uname -a
             - grep -i processor /proc/cpuinfo | wc -l
             - gcc --version
-            - apt-get update # required to install qt
-            - apt-get install -y xvfb qtbase5-dev libqt5svg5-dev qt5-default qttools5-dev-tools libqt5xmlpatterns5-dev libqt5core5a libqt5gui5 libqt5printsupport5 libqt5svg5 libqt5widgets5 libqt5xml5 libqt5xmlpatterns5 xpdf
             - mkdir build
             - cd build
             - qmake --version