[actions] Install fish using apt-get

For some reason, `test_ctrl_r` and `test_ctrl_r_abort` are not passing
on GitHub Action runner with Fish 3.2.0.

.github/workflows/linux.yml

@@ -23,16 +23,13 @@ jobs:
       with:
         go-version: ${{ matrix.go }}
 
-    - name: fish-actions/install-fish
-      uses: fish-actions/install-fish@v1.0.0
-
     - name: Setup Ruby
       uses: ruby/setup-ruby@v1.62.0
       with:
         ruby-version: 3.0.0
 
     - name: Install packages
-      run: sudo apt-get install --yes zsh tmux
+      run: sudo apt-get install --yes zsh fish tmux
 
     - name: Install Ruby gems
       run: sudo gem install --no-document minitest:5.14.2 rubocop:1.0.0 rubocop-minitest:0.10.1 rubocop-performance:1.8.1