ocaml 5: restrict lascar releases
They rely on `Stream`:
#=== ERROR while compiling lascar.0.7.0 =======================================#
# context 2.2.0~alpha~dev | linux/x86_64 | ocaml-base-compiler.5.0.0 | file:///home/opam/opam-repository
# path ~/.opam/5.0/.opam-switch/build/lascar.0.7.0
# command ~/.opam/opam-init/hooks/sandbox.sh build dune build -p lascar -j 31 @install
# exit-code 1
# env-file ~/.opam/log/lascar-8-eb833d.env
# output-file ~/.opam/log/lascar-8-eb833d.out
### output ###
# (cd _build/default && /home/opam/.opam/5.0/bin/ocamlc.opt -w -40 -g -bin-annot -I src/utils/.utils.objs/byte -no-alias-deps -open Utils -o src/utils/.utils.objs/byte/utils__Parsing.cmi -c -intf src/utils/parsing.mli)
# File "src/utils/parsing.mli", line 19, characters 19-27:
# 19 | -> (Genlex.token Stream.t -> 'a)
# ^^^^^^^^
# Error: Unbound module Stream