Update trunk for next OCaml release (#11293)

Signed-off-by: Marek Kubica <marek@tarides.com>

Author: Leonidas-from-XIV

.github/workflows/workflow.yml

@@ -33,7 +33,7 @@ jobs:
           - 5.1.x
         include:
           # OCaml trunk:
-          - ocaml-compiler: ocaml-variants.5.3.0+trunk
+          - ocaml-compiler: ocaml-variants.5.4.0+trunk
             os: ubuntu-latest
             skip_test: true
           # OCaml 4: