Bump lowest CI version to OCaml 4.08.0

Author: tjammer

.github/workflows/main.yml

@@ -17,7 +17,7 @@ jobs:
           - { ocaml-compiler: 4.14.0, os: ubuntu-latest }
           - { ocaml-compiler: 4.14.0, os: windows-latest }
           - { ocaml-compiler: 4.14.0, os: macos-latest }
-          - { ocaml-compiler: 4.06.0, os: ubuntu-latest }
+          - { ocaml-compiler: 4.08.0, os: ubuntu-latest }
 
     runs-on: ${{ matrix.os }}
 
@@ -41,10 +41,10 @@ jobs:
       - run: opam install . --deps-only
 
       - run: opam install containers re yojson -y
-        if: matrix.ocaml-compiler != '4.06.0'
+        if: matrix.ocaml-compiler != '4.08.0'
 
       - run: opam exec -- dune build
-        if: matrix.ocaml-compiler != '4.06.0'
+        if: matrix.ocaml-compiler != '4.08.0'
 
       - run: opam install raylib raygui
-        if: matrix.ocaml-compiler == '4.06.0'
+        if: matrix.ocaml-compiler == '4.08.0'