Android Dockerfile: add latest cmake 3.13.2

cmake 3.10 (which comes with Ubuntu 18.04) in combination with Qt 5.12
and the current qt-android-cmake causes an odd bug. Paths are set with a
double slash at the start '//' and later in the process this causes
garbled path names for some of the objects which in return causes the
APKs built in the container to fail.

Upgrading the cmake inside the container to 3.13.2 fixes that problem.

All the credit for identifying the problem and figuring out a solution
goes to Jan Mulder.

The resulting container was pushed to Docker hub as version to 5.12.03.

Reported-by: Jan Mulder <jlmulder@xs4all.nl>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

scripts/docker/android-build-container/Dockerfile

@@ -8,7 +8,6 @@ RUN apt-get update  && \
     git \
     libtool-bin \
     make \
-    cmake \
     wget \
     unzip \
     python \
@@ -28,6 +27,12 @@ ADD android-ndk-r*-linux-x86_64.zip /android/
 ADD sdk-tools-linux-*.zip /android/
 ADD android-build-wrapper.sh variables.sh qt-installer-noninteractive.qs /android/
 
+# install current cmake
+ADD cmake-3.13.2.tar.gz /android/
+RUN cd /android/cmake-3.13.2 && \
+    bash ./bootstrap && \
+    make -j6 && make install
+
 # run the build wrapper in prep mode
 RUN cd /android && bash -x /android/android-build-wrapper.sh -prep-only
 
@@ -43,7 +48,8 @@ RUN cd /android && \
 	   android-ndk-r*-linux-x86_64.zip \
            android-sdk-linux/emulator \
            $( find android-ndk*/platforms -name arch-mips -o -name arch-x86 ) \
-           android-ndk*/toolchains/x86-* android-ndk*/toolchains/llvm/prebuilt/x86-* && \
+           android-ndk*/toolchains/x86-* android-ndk*/toolchains/llvm/prebuilt/x86-* \
+           cmake-3.13* && \
     ls -l && \
     du -sh *
 RUN apt-get clean