Update Dockerfile for Ruby 3.1

While working on Ruby 3 support several months ago, I noticed the
[Dockerfile](https://github.com/jekyll/classifier-reborn/blob/c3e5a84c3e0915d20ab52f2b783703575584d4a2/Dockerfile)
was really stale. I didn't immediately fix this at the time, but made a
mental note to come back to it sometime.

This Dockerfile is intended to be used for development. It was added in
jekyll#104 (discussed in
detail at jekyll#101). The
documentation for using this is still available (and accurate) at
https://jekyll.github.io/classifier-reborn/development#development-using-docker.

classifier-reborn currently supports ruby 2.7, 3.0, and 3.1 (as you can
see in `ci.yml`). Since we can only (easily) put one ruby version in the
Dockerfile, using the most recent version made sense to me. Doing so
means we have to use Numo instead of GSL since GSL isn't currently
supported on Ruby 3.x.

Author: mkasberg

Dockerfile

@@ -1,10 +1,9 @@
-FROM ruby:2.4
-MAINTAINER Sawood Alam <https://github.com/ibnesayeed>
+FROM ruby:3.1
 
 ENV LANG C.UTF-8
 
-RUN apt update && apt install -y libgsl0-dev && rm -rf /var/lib/apt/lists/*
-RUN gem install narray nmatrix gsl jekyll github-pages
+RUN apt update && apt install -y liblapacke-dev libopenblas-dev && rm -rf /var/lib/apt/lists/*
+RUN gem install numo-narray numo-linalg jekyll github-pages
 
 RUN cd /tmp \
     && wget http://download.redis.io/redis-stable.tar.gz \