Support Ruby 3.4 (#40)

* Test against Ruby 3.4
* Bump `webmock` dev dependency (breaks due to `base64` being removed from stdlib in Ruby 3.4)

Author: fbacall

.github/workflows/tests.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: ['2.7', '3.0', '3.1', '3.2', '3.3']
+        ruby: ['2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
       fail-fast: false
     steps:
       - name: Checkout

.ruby-version

@@ -1 +1 @@
-ruby-3.2.5
+ruby-3.4.9

ro_crate.gemspec

@@ -14,6 +14,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'test-unit', '~> 3.5.3'
   s.add_development_dependency 'simplecov', '~> 0.21.2'
   s.add_development_dependency 'yard', '~> 0.9.25'
-  s.add_development_dependency 'webmock', '~> 3.8.3'
+  s.add_development_dependency 'webmock', '~> 3.26.2'
   s.add_development_dependency 'rexml', '~> 3.4.4'
 end