session-cohttp-async.0.4.* was linking result transitively

[mseri]

And now fails since dependencies are no longer using it

#=== ERROR while compiling session-cohttp-async.0.4.0 =========================#
# context              2.2.0~alpha4~dev | linux/x86_64 | ocaml-base-compiler.4.14.1 | file:///home/opam/opam-repository
# path                 ~/.opam/4.14/.opam-switch/build/session-cohttp-async.0.4.0
# command              ~/.opam/opam-init/hooks/sandbox.sh build jbuilder build -p session-cohttp-async
# exit-code            1
# env-file             ~/.opam/log/session-cohttp-async-7-5cd187.env
# output-file          ~/.opam/log/session-cohttp-async-7-5cd187.out
### output ###
# File "cohttp/async/jbuild", line 6, characters 36-42:
# Error: Library "result" not found.
# Hint: try: jbuilder external-lib-deps --missing -p session-cohttp-async @install