check ocaml 5.3

Author: ospencer

.github/workflows/opam.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        ocaml-compiler: [4.13.1, 4.14.1, 4.14.2, 4.14.3, 5.3.1]
+        ocaml-compiler: [5.3.0]
 
     steps:
       - name: Checkout project