Update ci.yml go version to 1.21

Author: ghostiam

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
           fetch-depth: 2
       - uses: actions/setup-go@v2
         with:
-          go-version: '1.13'
+          go-version: '1.21'
       - name: Run coverage
         run: go test -race -coverprofile=coverage.txt -covermode=atomic
       - name: Upload coverage to Codecov