Update CI to reflect promotion to master.

.gitlab-ci.yml

@@ -14,11 +14,11 @@ variables:
   - git clone https://gitlab.mpi-sws.org/iris/ci.git ci -b opam2
   - ci/buildjob
   cache:
-    key: "$CI_JOB_NAME-gen_proofmode"
+    key: "$CI_JOB_NAME-master"
     paths:
     - opamroot/
   only:
-  - gen_proofmode
+  - master
   - /^ci/
   except:
   - triggers