ci: Remove CodeCov (#7663)

This has been broken for PRs since April 2021. As it's only used for PRs and there has been no one interested in correcting it all this time, it has been removed as it's redundant.

Signed-off-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>

.codecov.yml

@@ -1,8 +0,0 @@
-coverage:
-  status:
-    project:
-      default:
-        target: 50%
-        threshold: null
-    patch: false
-    changes: false

.github/workflows/go.coverage.yml

@@ -1,34 +0,0 @@
-name: Go Coverage
-on: [pull_request]
-permissions:
-  contents: read
-
-jobs:
-  test:
-    name: Coverage
-    runs-on: ubuntu-latest
-    steps:
-      - name: Check out code
-        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0
-
-      - name: Setup Go Version
-        run: echo "GO_VERSION=$(cat .go-version)" >> $GITHUB_ENV
-
-      - name: Install Go
-        uses: actions/setup-go@44694675825211faa026b3c33043df3e48a5fa00  # v6.0.0
-        with:
-          go-version: ${{ env.GO_VERSION }}
-        id: go
-
-      - name: Build
-        run: go build -v ./...
-
-      - name: Test With Coverage
-        run: |
-          go install github.com/fatih/faillint@c56e3ec6dbfc933bbeb884fd31f2bcd41f712657 # v1.15.0
-          for d in request core coremain plugin test; do \
-             ( cd $d; go test -coverprofile=cover.out -covermode=atomic -race ./...; [ -f cover.out ] && cat cover.out >> ../coverage.txt ); \
-          done
-
-      - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@5a1091511ad55cbe89839c7260b706298ca349f7  # v5.5.1

README.md

@@ -4,7 +4,6 @@
 ![CodeQL](https://github.com/coredns/coredns/actions/workflows/codeql-analysis.yml/badge.svg)
 ![Go Tests](https://github.com/coredns/coredns/actions/workflows/go.test.yml/badge.svg)
 [![CircleCI](https://circleci.com/gh/coredns/coredns.svg?style=shield)](https://circleci.com/gh/coredns/coredns)
-[![Code Coverage](https://img.shields.io/codecov/c/github/coredns/coredns/master.svg)](https://codecov.io/github/coredns/coredns?branch=master)
 [![Docker Pulls](https://img.shields.io/docker/pulls/coredns/coredns.svg)](https://hub.docker.com/r/coredns/coredns)
 [![Go Report Card](https://goreportcard.com/badge/github.com/coredns/coredns)](https://goreportcard.com/report/coredns/coredns)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1250/badge)](https://bestpractices.coreinfrastructure.org/projects/1250)