port blake2 to 5.2.1

Author: glyh

src/lib/blake2/blake2.ml

@@ -1,4 +1,4 @@
-open Core_kernel
+open Core
 
 module Make () = struct
   let digest_size_in_bits = 256

src/lib/blake2/dune

@@ -4,14 +4,15 @@
  (instrumentation
   (backend bisect_ppx))
  (preprocess
-  (pps ppx_compare ppx_deriving_yojson ppx_jane ppx_mina ppx_version))
+  (pps ppx_assert ppx_compare ppx_deriving_yojson ppx_hash ppx_inline_test ppx_mina ppx_sexp_conv ppx_version))
  (inline_tests
   (flags -verbose -show-counts))
  (libraries
   ;; opam libraries
   base.base_internalhash_types
   bigarray-compat
   bin_prot.shape
+  core_kernel; TODO: figure out why we still need core_kernel here
   digestif
   ppx_inline_test.config
   sexplib0

src/lib/blake2/intf.ml

@@ -1,4 +1,4 @@
-open Core_kernel
+open Core
 
 module type S = sig
   val digest_size_in_bits : int