do nightly build against Coq 8.10 branch

.gitlab-ci.yml

@@ -37,7 +37,8 @@ build-coq.8.8.2:
 build-iris.dev:
   <<: *template
   variables:
-    OPAM_PINS: "coq version 8.8.2   coq-stdpp.dev git git+https://gitlab.mpi-sws.org/iris/stdpp.git#$STDPP_REV   coq-iris.dev git git+https://gitlab.mpi-sws.org/FP/iris-coq.git#$IRIS_REV"
+    OCAML: "ocaml-base-compiler.4.07.0"
+    OPAM_PINS: "coq version 8.10.dev   coq-stdpp.dev git git+https://gitlab.mpi-sws.org/iris/stdpp.git#$STDPP_REV   coq-iris.dev git git+https://gitlab.mpi-sws.org/FP/iris-coq.git#$IRIS_REV"
   except:
   only:
   - triggers