[dune] Fix bad interaction among PR #8627 and #8657

Dangers of not stacking PRs hit again, and here we hit a problem
breaking the build on master due to #8627 adding a new file to install
with for the (implicit) `coq` package and #8657 removing the implicit
status of such package.

1 files changed, 1 insertions, 0 deletions

diff --git a/dune b/dune
index 0a0ff213ed..b3073493ea 100644
--- a/dune
+++ b/dune
@@ -18,6 +18,7 @@
 
 (install
  (section lib)
+ (package coq)
  (files
    revision))