Add .rubocop_todo.yml to RuboCop cache of GHA workflow template

Follow-up to rails#54754.

At the time of running `rails new`, .rubocop_todo.yml does not exist.
This file is automatically generated by commands such as `rubocop --auto-gen-config`.
If changes in caching behavior occur after such a command generates .rubocop_todo.yml,
it may be difficult to notice the impact.

With this change, users no longer need to worry about the presence of .rubocop_todo.yml,
which is frequently used with RuboCop, in relation to the cache in GHA workflows.

Author: koic

railties/lib/rails/generators/rails/app/templates/github/ci.yml.tt

@@ -60,7 +60,7 @@ jobs:
       - name: Prepare RuboCop cache
         uses: actions/cache@v4
         env:
-          DEPENDENCIES_HASH: ${{ hashFiles('.ruby-version', '**/.rubocop.yml', 'Gemfile.lock') }}
+          DEPENDENCIES_HASH: ${{ hashFiles('.ruby-version', '**/.rubocop.yml', '**/.rubocop_todo.yml', 'Gemfile.lock') }}
         with:
           path: ${{ env.RUBOCOP_CACHE_ROOT }}
           key: rubocop-${{ runner.os }}-${{ env.DEPENDENCIES_HASH }}-${{ github.ref_name == github.event.repository.default_branch && github.run_id || 'default' }}

railties/lib/rails/generators/rails/plugin/templates/github/ci.yml.tt

@@ -25,7 +25,7 @@ jobs:
       - name: Prepare RuboCop cache
         uses: actions/cache@v4
         env:
-          DEPENDENCIES_HASH: ${{ hashFiles('**/.rubocop.yml', 'Gemfile.lock') }}
+          DEPENDENCIES_HASH: ${{ hashFiles('**/.rubocop.yml', '**/.rubocop_todo.yml', 'Gemfile.lock') }}
         with:
           path: ${{ env.RUBOCOP_CACHE_ROOT }}
           key: rubocop-${{ runner.os }}-${{ env.RUBY_VERSION }}-${{ env.DEPENDENCIES_HASH }}-${{ github.ref_name == github.event.repository.default_branch && github.run_id || 'default' }}