ocaml 5: restrict owl-base releases
They rely on `Pervasives`:
#=== ERROR while compiling owl-base.0.6.0 =====================================#
# 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/owl-base.0.6.0
# command ~/.opam/opam-init/hooks/sandbox.sh build dune build -p owl-base -j 127
# exit-code 1
# env-file ~/.opam/log/owl-base-8-253801.env
# output-file ~/.opam/log/owl-base-8-253801.out
### output ###
...
# (cd _build/default && /home/opam/.opam/5.0/bin/ocamlc.opt -w -40 -safe-string -g -bin-annot -I src/base/.owl_base.objs/byte -intf-suffix .ml -no-alias-deps -o src/base/.owl_base.objs/byte/owl_base_complex.cmo -c -impl src/base/owl_base_complex.ml)
# File "src/base/maths/owl_base_complex.ml", line 32, characters 2-12:
# Error: Unbound module Pervasives