remove unnecessary comments

Author: hiraokashi

.github/workflows/ci.yml

@@ -9,9 +9,6 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest, macos-latest ]
-        # TODO: Wait for supporting Ruby 3.0 in simplecov-cobertura.
-        # See https://github.com/dashingrocket/simplecov-cobertura/pull/16
-        # ruby: [ 2.5, 2.6, 2.7, 3.0 ]
         ruby: [ '3.0', '3.1', '3.2', '3.3' ]
         exclude:
          - { os: macos-latest, ruby: '2.5' }