build: upgrade ruby

Upgrade Ruby, adding `csv` and `racc` to the `Gemfile` as these are no
longer provided in the Ruby standard library.

Dockerfile

 ###############################################################################
 # `base` image for all downstream images to build upon.
 # Make sure the ruby version matches the version in the Gemfile.
-FROM ruby:3.0.7-slim AS base
+FROM ruby:3.4.2-slim AS base
 
 RUN set -eux; \
     apt-get -q update; \

Gemfile

 source 'https://rubygems.org'
 
 # Make sure the ruby version matches the version in the Dockerfile.
-ruby '3.0.7'
+ruby '3.4.2'
 
 gem 'gitlab-triage', '~> 1.44', '>= 1.44.3'
+gem 'csv'
+gem 'racc'

Gemfile.lock

@@ -19,6 +19,7 @@ GEM
     bigdecimal (3.1.9)
     concurrent-ruby (1.3.5)
     connection_pool (2.5.0)
+    csv (3.3.2)
     drb (2.2.1)
     gitlab-triage (1.44.3)
       activesupport (>= 5.1)
@@ -46,6 +47,7 @@ GEM
     minitest (5.25.4)
     multi_xml (0.6.0)
     mutex_m (0.3.0)
+    racc (1.8.1)
     securerandom (0.3.2)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
@@ -55,10 +57,12 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  csv
   gitlab-triage (~> 1.44, >= 1.44.3)
+  racc
 
 RUBY VERSION
-   ruby 3.0.7p220
+   ruby 3.4.2p28
 
 BUNDLED WITH
    2.5.23