bump the Coq version we test

.gitlab-ci.yml

@@ -33,10 +33,10 @@ build-coq.dev:
   variables:
     OPAM_PINS: "coq version dev"
 
-build-coq.8.12.0:
+build-coq.8.13.1:
   <<: *template
   variables:
-    OPAM_PINS: "coq version 8.12.0"
+    OPAM_PINS: "coq version 8.13.1"
     OPAM_PKG: "1"
     DENY_WARNINGS: "1"
   tags:

README.md

@@ -6,7 +6,7 @@ This is the Coq development accompanying lambda-Rust.
 
 This version is known to compile with:
 
- - Coq 8.12.0
+ - Coq 8.13.1
  - A development version of [Iris](https://gitlab.mpi-sws.org/iris/iris)
 
 ## Building from source