docs: fix badge in README (#28796)

* Fix broken badge in README.md

Replaced broken Github link with IPFS link for long-term storage.

* update go badge

Co-authored-by: lightclient <14004106+lightclient@users.noreply.github.com>

---------

Co-authored-by: lightclient <14004106+lightclient@users.noreply.github.com>

README.md

@@ -3,7 +3,7 @@
 Official Golang execution layer implementation of the Ethereum protocol.
 
 [![API Reference](
-https://camo.githubusercontent.com/915b7be44ada53c290eb157634330494ebe3e30a/68747470733a2f2f676f646f632e6f72672f6769746875622e636f6d2f676f6c616e672f6764646f3f7374617475732e737667
+https://pkg.go.dev/badge/github.com/ethereum/go-ethereum
 )](https://pkg.go.dev/github.com/ethereum/go-ethereum?tab=doc)
 [![Go Report Card](https://goreportcard.com/badge/github.com/ethereum/go-ethereum)](https://goreportcard.com/report/github.com/ethereum/go-ethereum)
 [![Travis](https://travis-ci.com/ethereum/go-ethereum.svg?branch=master)](https://travis-ci.com/ethereum/go-ethereum)