Not installable/pinnable with opam

[sim642]

Trying to install or pin Gobview with opam errors:

#=== ERROR while compiling gobview.~dev =======================================#
# context     2.1.2 | linux/x86_64 | ocaml-variants.4.14.0+options | pinned(git+file:///home/simmo/dev/goblint/sv-comp/goblint/gobview#master#eb6ff918)
# path        ~/dev/goblint/sv-comp/goblint/_opam/.opam-switch/build/gobview.~dev
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p gobview -j 15 @install
# exit-code   1
# env-file    ~/.opam/log/gobview-2650379-99c6a1.env
# output-file ~/.opam/log/gobview-2650379-99c6a1.out
### output ###
# File "goblint-http-server/dune", line 4, characters 30-35:
# 4 |  (promote (until-clean) (into ../..))
#                                   ^^^^^
# Error: path outside the workspace: ../.. from goblint-http-server

Of course we've meant to use it as a submodule of Goblint but it would be nice if it at least didn't error like this. Pinning in opam is needed for generating lock files correctly.