use Ubuntu cosmic for base image

This will easily allow newer version of Qt but mainly SIP for auto build of the Python API docs.

Author: 3nids

.ci/travis/linux/docker-build-test.sh

@@ -59,6 +59,9 @@ cmake \
  -DPYTHON_TEST_WRAPPER="timeout -sSIGSEGV 55s"\
  -DCXX_EXTRA_FLAGS="${CLANG_WARNINGS}" \
  -DWERROR=TRUE \
+ -DQT5_3DEXTRA_LIBRARY="/usr/lib/x86_64-linux-gnu/libQt53DExtras.so" \
+ -DQT5_3DEXTRA_INCLUDE_DIR="/root/QGIS/external/qt3dextra-headers" \
+ -DCMAKE_PREFIX_PATH="/root/QGIS/external/qt3dextra-headers/cmake" \
  ..
 echo "travis_fold:end:cmake"
 

.docker/qgis3-build-deps.dockerfile

@@ -1,4 +1,4 @@
-FROM      ubuntu:18.04
+FROM      ubuntu:18.10
 MAINTAINER Denis Rouzaud <denis@opengis.ch>
 
 LABEL Description="Docker container with QGIS dependencies" Vendor="QGIS.org" Version="1.0"
@@ -35,6 +35,7 @@ RUN  apt-get update \
     libproj-dev \
     libqca-qt5-2-dev \
     libqca-qt5-2-plugins \
+    libqt53dextras5 \
     libqt53drender5 \
     libqt5concurrent5 \
     libqt5opengl5-dev \
@@ -89,7 +90,6 @@ RUN  apt-get update \
     qt5keychain-dev \
     qtbase5-dev \
     qtdeclarative5-dev-tools \
-    qtdeclarative5-qtquick2-plugin \
     qtpositioning5-dev \
     qttools5-dev \
     qttools5-dev-tools \