ubuntu.yml in lutaml-0.3.2

- old
+ new

@@ -16,10 +16,10 @@
     runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.experimental }}
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '2.6', '2.5', '2.4' ]
+        ruby: [ '2.6', '2.5' ]
         experimental: [false]
         include:
           - ruby: '2.7'
             experimental: true
     steps: