Opam eval for FPTaylor build

Author: NoxNovus

.github/workflows/fptaylor.yml

@@ -22,6 +22,7 @@ jobs:
       - name: Install OCaml dependencies
         run: |
           opam install -y num
+          eval $(opam env)
 
       - name: Set up Python 3.7
         uses: actions/setup-python@v4