fix: CI: install missing opam deps

Author: Simon Cruanes

.github/workflows/test.yml

@@ -12,11 +12,11 @@ jobs:
         - 4.14.2
 
     steps:
-    - uses: actions/checkout@v2
-    - uses: ocaml/setup-ocaml@v2
+    - uses: actions/checkout@v4
+    - uses: ocaml/setup-ocaml@v3
       with:
         ocaml-compiler: ${{matrix.ocaml}}
-    - run: sudo apt-get install python-bs4
+    - run: sudo apt-get install python3-bs4
     - run: opam install --deps-only --with-test . --yes
     - run: opam install js_of_ocaml --yes
 

markup.opam

@@ -18,6 +18,8 @@ depends: [
   "uutf" {>= "1.0.0"}
 
   "bisect_ppx" {dev & >= "2.5.0"}
+  "containers" {with-test}
+  "devkit" {with-test}
   "ounit2" {dev}
 ]
 # Markup.ml implicitly requires OCaml 4.02.3, as this is a contraint of Dune.