version of SWIG should be updated in Dcokerfile

[Page-David]

When I built the code with the scripts/docker/ubuntu18.04/Dockerfile, I found the Installation of SWIG part should be updated as the requirements of SWIG is now 4.1.1.

So chnage this

RUN mkdir -p ~/opensim-workspace/swig-source || true
WORKDIR ~/opensim-workspace/swig-source
RUN wget -nc -q --show-progress https://github.com/swig/swig/archive/refs/tags/rel-4.0.2.tar.gz
RUN tar xzf rel-4.0.2.tar.gz
WORKDIR ./swig-rel-4.0.2
RUN ./autogen.sh && ./configure --prefix=$HOME/swig --disable-ccache
RUN make && make -j$NUM_JOBS install 

to

# Download and install SWIG 4.1.1.
RUN mkdir -p ~/opensim-workspace/swig-source || true
RUN apt-get install -y libpcre2-dev
WORKDIR ~/opensim-workspace/swig-source
RUN wget -nc -q --show-progress https://github.com/swig/swig/archive/refs/tags/v4.1.1.tar.gz
RUN tar xzf v4.1.1.tar.gz
WORKDIR ./swig-4.1.1
RUN ./autogen.sh && ./configure --prefix=$HOME/swig --disable-ccache
RUN make && make -j$NUM_JOBS install  

[nickbianco]

Hi @Page-David, thanks for making a note of this. That Dockerfile is pretty out of date. Would you be interested in opening a PR since you already have a code fix here?