add trigger to build against specific iris version

.gitlab-ci.yml

@@ -27,6 +27,8 @@ build-coq8.7:
   <<: *template
   variables:
     OPAM_PINS: "coq version 8.7.dev   coq-mathcomp-ssreflect version dev"
+  except:
+  - triggers
 
 build-coq8.6.1:
   <<: *template
@@ -37,3 +39,12 @@ build-coq8.6.1:
     paths:
     - build-time.txt
     - build-env.txt
+  except:
+  - triggers
+
+build-iris.dev:
+  <<: *template
+  variables:
+    OPAM_PINS: "coq version 8.6.1   coq-mathcomp-ssreflect version 1.6.1   coq-iris.dev git https://gitlab.mpi-sws.org/FP/iris-coq.git#$REV"
+  only:
+  - triggers