centos-7: Add missing gstreamer runtime dependency for Qt

centos-7/Dockerfile

@@ -103,6 +103,7 @@ RUN version=5.12.6 && \
     yum install -y \
         pulseaudio-libs \
         pulseaudio-libs-glib2 \
+        gstreamer1-plugins-base \
         && \
     yum clean all && \
     source /etc/profile && \