chore(rln-relay): bump zerokit and update ffi

[rymnc]

Changes and optimizations included in zerokit's bump - vacp2p/zerokit@005393d...master

This included ffi changes -

-proc hash*(ctx: ptr RLN,
-           input_buffer: ptr Buffer,
-           output_buffer: ptr Buffer): bool {.importc: "hash".}
+#-------------------------------- Hashing utils -------------------------------------------
+
+proc sha256*(input_buffer: ptr Buffer,
+             output_buffer: ptr Buffer): bool {.importc: "hash".}
 ## it hashes (sha256) the plain text supplied in inputs_buffer and then maps it to a field element
 ## this proc is used to map arbitrary signals to field element for the sake of proof generation
 ## inputs_buffer holds the hash input as a byte seq
 ## the hash output is generated and populated inside output_buffer
 ## the output_buffer contains 32 bytes hash output
+
+proc poseidon*(input_buffer: ptr Buffer,
+               output_buffer: ptr Buffer): bool {.importc: "poseidon_hash".}
+## it hashes (poseidon) the plain text supplied in inputs_buffer
+## this proc is used to compute the identity secret hash, and external nullifier
+## inputs_buffer holds the hash input as a byte seq
+## the hash output is generated and populated inside output_buffer
+## the output_buffer contains 32 bytes hash output

Note that we've changed the proc name since it conflicted with hash() generated in hashcommon.nim (stdlib), and since it is more indicative of the underlying hash function.

Required as a prerequisite to #1451

[LNSD]

LGTM ✅

One little comment for the future :)

[LNSD]

Knowing that this is out of this PR's scope, I recommend revisiting the log levels within the module.

In this diff snippet, for example, the log level should be set to trace.

[rymnc]

agreed!