ocaml-src 4.13.1

Error log

The package failed to build. The error log from opam follows.

[ERROR] Package conflict!
  * Incompatible packages:
    - (invariant) -> ocaml-base-compiler = 5.1.1
    - ocaml-src = 4.13.1 -> ocaml = 4.13.1 -> ocaml-variants < 4.13.2~
    You can temporarily relax the switch invariant with `--update-invariant'
  * Missing dependency:
    - ocaml-src = 4.13.1 -> ocaml = 4.13.1 -> ocaml-variants < 4.13.2~ -> ocaml-beta
    unmet availability conditions: 'enable-ocaml-beta-repository'

No solution found, exiting