Run opam reinstall ocamlfind to fix opam

Author: polytypic

.github/workflows/main.yml

@@ -41,8 +41,10 @@ jobs:
           cache-prefix: ${{ steps.multicore_hash.outputs.commit }}
           opam-depext: false
 
+      - run: opam reinstall ocamlfind
+
       - run: opam install . --deps-only --with-test
 
       - run: opam exec -- dune build
 
-      - run: opam exec -- dune runtest
+      - run: opam exec -- dune runtest