Support OCaml 5

Use latest gapi-ocaml version

Author: astrada

src/dune

@@ -2,4 +2,5 @@
  (name google_drive_ocamlfuse)
  (wrapped false)
  (flags :standard -w -3-27-32-58)
- (libraries cryptokit extlib gapi-ocaml ocamlfuse sqlite3 threads camlidl tiny_httpd))
+ (libraries cryptokit extlib gapi-ocaml gapi-ocaml.netsys-local ocamlfuse
+            sqlite3 threads camlidl tiny_httpd))

src/mime.ml

@@ -2,7 +2,7 @@ open GapiUtils.Infix
 
 let map_filename_to_mime_type filename =
   let extension =
-    try GapiUtils.string_after_char '.' filename |> String.lowercase
+    try GapiUtils.string_after_char '.' filename |> String.lowercase_ascii
     with Not_found -> ""
   in
   match extension with