ci: remove code cov

.github/workflows/go.yml

@@ -31,13 +31,7 @@ jobs:
       - name: Build
         run: go build -v .
 
-      - name: Test and Coverage
+      - name: Test
         run: |
           export PATH=$PATH:$(go env GOPATH)/bin
-          go test -v -coverpkg=./... -covermode=atomic -coverprofile coverage.txt ./...
-
-      - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v4
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          fail_ci_if_error: true
+          go test -v ./...

README.md

@@ -3,7 +3,6 @@
 [![Go Reference](https://pkg.go.dev/badge/github.com/celestiaorg/nmt.svg)](https://pkg.go.dev/github.com/celestiaorg/nmt)
 ![golangci-lint](https://github.com/celestiaorg/nmt/workflows/lint/badge.svg)<!-- it retrieves the lint workflow status badge for the default branch i.e., main, for a different branch, specify the branch parameter in the URL() -->
 ![Go](https://github.com/celestiaorg/nmt/workflows/Go/badge.svg)
-![codecov.io](https://codecov.io/github/celestiaorg/nmt/coverage.svg?branch=main)
 
 A Namespaced Merkle Tree is
 > [...] an ordered Merkle tree that uses a modified hash function