install ocamlformat

Author: aspeddro

.github/workflows/ci.yml

@@ -186,7 +186,10 @@ jobs:
 
       - name: Install OPAM dependencies
         if: steps.cache-opam-env.outputs.cache-hit != 'true'
-        run: opam install . --deps-only
+        run: |
+          opam install . --deps-only
+          opam install ocamlformat=$(grep "version" .ocamlformat | awk -F"= " '{print $2}')
+
 
       - name: Cache OPAM environment
         if: steps.cache-opam-env.outputs.cache-hit != 'true'