ignore rails 4.2 and ruby 2.7, remove ruby 2.4

Author: mathieujobin

.github/workflows/build.yml

@@ -20,7 +20,6 @@ jobs:
           - 2.7
           - 2.6
           - 2.5
-          - 2.4
           - jruby-9.2.17.0
         gemfile:
           - Gemfile-4-2-stable
@@ -33,6 +32,8 @@ jobs:
           - Gemfile-6-1-sprockets-3
           - Gemfile-6-1-sprockets-4
         exclude:
+        - gemfile: Gemfile-4-2-stable
+          ruby: 2.7
         - gemfile: Gemfile-4-2-stable
           ruby: 3.0
         - gemfile: Gemfile-5-0-stable