Use deb10 for linux builds

Author: hasufell

.gitlab-ci.yml

@@ -58,7 +58,7 @@ build-x86_64-linux:
   extends: .build
   tags:
     - x86_64-linux
-  image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb9:$DOCKER_REV"
+  image: "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-deb10:$DOCKER_REV"
   parallel: *default_matrix
 
 build-x86_64-linux-alpine: