Upgrade to Qt 6.4.1

The build unfortunately fail due to too old CMake version.

Proposal for root-cause fix: emscripten-core/emsdk#1135

image/Dockerfile

@@ -12,7 +12,7 @@ RUN cp GE_External_Root_CA_2_1.crt /usr/local/share/ca-certificates/
 RUN update-ca-certificates
 
 # Clone Qt sources
-RUN git clone --branch=5.15.2 https://code.qt.io/qt/qt5.git
+RUN git clone --branch=6.4.1 https://code.qt.io/qt/qt5.git
 WORKDIR /development/qt5
 RUN ./init-repository
 
@@ -35,7 +35,7 @@ RUN cp GE_External_Root_CA_2_1.crt /usr/local/share/ca-certificates/
 RUN update-ca-certificates
 
 # Copy Qt binaries to new container
-COPY --from=qtbuilder /usr/local/Qt-5.15.2/ /usr/local/Qt-5.15.2/
+COPY --from=qtbuilder /usr/local/Qt-6.4.1/ /usr/local/Qt-6.4.1/
 
 # Install Boost & Eigen
 # https://docs.docker.com/develop/develop-images/dockerfile_best-practices/
@@ -49,7 +49,7 @@ RUN mkdir -p /project/dependencies/include && mkdir -p /project/dependencies/lib
     ln -s /usr/include/boost   /project/dependencies/include/boost  && \
     ln -s /usr/include/eigen3  /project/dependencies/include/eigen3 && \
     ln -s /usr/lib/cmake       /project/dependencies/lib/cmake      && \
-    ln -s /usr/local/Qt-5.15.2 /project/Qt
+    ln -s /usr/local/Qt-6.4.1  /project/Qt
 
 # Add qmake to PATH (doesn't seem to work)
 #ENV PATH="/project/Qt/bin:${PATH}"