Improved GitHub workflow

Author: mmottl

.github/workflows/main.yml

@@ -12,23 +12,23 @@ jobs:
       matrix:
         include:
           - os: ubuntu-latest
-            ocaml-compiler: 4.14.0
+            ocaml-compiler: 5.2.0
           - os: macos-latest
-            ocaml-compiler: 4.13.1
+            ocaml-compiler: 5.2.0
 
     runs-on: ${{ matrix.os }}
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
         uses: ocaml/setup-ocaml@v2
         with:
           ocaml-compiler: ${{ matrix.ocaml-compiler }}
 
       - run: opam install -t --deps-only .
-      
+
       - run: opam exec -- make
-      
+
       - run: opam exec -- make -C test