nuscr 2.0.0 is not compatible with base v0.17
Fails with
```
# File "lib/syntaxtree/syntax.ml", line 81, characters 24-43:
# 81 | let pp_payloadt fmt p = Caml.Format.fprintf fmt "%s" (show_payloadt p)
# ^^^^^^^^^^^^^^^^^^^
# Error: Unbound module "Caml.Format"
```