docs: fixed widget and link, go report A+ (#354)

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## Overview

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## Summary by CodeRabbit

- **Documentation**
  - Removed the Go Report Card badge from the README.md file.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: Olexandr88

Diff for: README.md

@@ -3,7 +3,6 @@
 <!-- markdownlint-disable MD013 MD041 -->
 
 [![GoDoc](https://img.shields.io/badge/godoc-reference-blue?style=flat-square&logo=go)](https://godoc.org/github.com/celestiaorg/blobstream-contracts)
-[![Go Report Card](https://goreportcard.com/badge/github.com/celestiaorg/blobstream-contracts?style=flat-square)](https://goreportcard.com/report/github.com/celestiaorg/blobstream-contracts)
 [![Version](https://img.shields.io/github/tag/celestiaorg/blobstream-contracts.svg?style=flat-square)](https://github.com/celestiaorg/blobstream-contracts/releases/latest)
 [![License: Apache-2.0](https://img.shields.io/github/license/celestiaorg/blobstream-contracts.svg?style=flat-square)](https://github.com/celestiaorg/blobstream-contracts/blob/master/LICENSE)