GHA: skip performance comparison with BS4

It appears that BS4 is no longer available in the Ubuntu package repos,
and we don't really benefit much from comparing with it, so we can just
skip this test.

.github/workflows/test.yml

@@ -27,10 +27,8 @@ jobs:
     - uses: ocaml/setup-ocaml@v2
       with:
         ocaml-compiler: ${{matrix.ocaml}}
-    - run: sudo apt-get install python-bs4
     - run: opam install --deps-only --with-test . --yes
     - run: opam exec -- make test
-    - run: opam exec -- make performance-test
     - run: opam lint
     - if: ${{matrix.ocaml == '4.13.1'}}
       env: