docs: fix link (#1472)

I found that the previous link is expired due to the structure change.
dedf0d2#diff-f281ecc03994c15559193760bfdc29b0e4c448bf2abada106131842838931549

Updated it with hash in case it missing again.

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Co-authored-by: CHAMI Rachid <chamirachid1@gmail.com>

abci/README.md

@@ -19,7 +19,7 @@ To get up and running quickly, see the [getting started guide](../docs/app-dev/g
 A detailed description of the ABCI methods and message types is contained in:
 
 - [The main spec](https://github.com/cometbft/cometbft/blob/v0.34.x/spec/abci/README.md)
-- [A protobuf file](./types/types.proto)
+- [A protobuf file](../proto/abci/types.proto)
 - [A Go interface](./types/application.go)
 
 ## Protocol Buffers