CI: Test with ruby 3.0 as the latest ruby version

.github/workflows/liquid.yml

@@ -6,9 +6,8 @@ jobs:
     strategy:
       matrix:
         entry:
-          - { ruby: 2.5, allowed-failure: false }
-          - { ruby: 2.6, allowed-failure: false }
-          - { ruby: 2.7, allowed-failure: false }
+          - { ruby: 2.5, allowed-failure: false } # minimum supported
+          - { ruby: 3.0, allowed-failure: false } # latest
           - { ruby: ruby-head, allowed-failure: true }
     name: test (${{ matrix.entry.ruby }})
     steps:

test/integration/context_test.rb

@@ -461,6 +461,7 @@ class ContextTest < Minitest::Test
   end
 
   def test_interrupt_avoids_object_allocations
+    @context.interrupt? # ruby 3.0.0 allocates on the first call
     assert_no_object_allocations do
       @context.interrupt?
     end