Upgrade to Melange 4.0.1-52 and OCaml 5.2.0

[feihong]

Tried to do it in this branch but ran into this error involving styled-ppx not liking ocaml 5.2.0:

$ npm run init

> init
> opam switch create . 5.2.0 -y --deps-only && npm run install:npm-opam


<><> Installing new switch packages <><><><><><><><><><><><><><><><><><><><><><>
Switch invariant: ["ocaml-base-compiler" {= "5.2.0"} | "ocaml-system" {= "5.2.0"}]
fin
[ERROR] Could not determine which packages to install for this switch:
  * No agreement on the version of ocaml:
    - (invariant) → ocaml-base-compiler = 5.2.0 → ocaml = 5.2.0
    - melange-for-react-devs → styled-ppx >= 0.59.1 → ocaml < 5.2.0
    You can temporarily relax the switch invariant with `--update-invariant'
  * No agreement on the version of ocaml-base-compiler:
    - (invariant) → ocaml-base-compiler = 5.2.0
    - melange-for-react-devs → styled-ppx >= 0.59.1 → ocaml < 5.2.0 → ocaml-base-compiler < 3.07+1
  * Missing dependency:
    - melange-for-react-devs → styled-ppx >= 0.59.1 → ocaml < 5.2.0 → ocaml-variants → ocaml-beta
    unmet availability conditions: 'enable-ocaml-beta-repository'
  * Missing dependency:
    - melange-for-react-devs → styled-ppx >= 0.59.1 → ocaml < 5.2.0 → ocaml-variants → system-msvc
    unmet availability conditions: 'os = "win32"'

cc @davesnx

[feihong]

styled-ppx updated so that CI succeeds with OCaml 5.2: davesnx/styled-ppx#518