ci: Update go-version matrix (#319)

Signed-off-by: GitHub <noreply@github.com>
Co-authored-by: chizhg <chizhg@users.noreply.github.com>

Author: chizhg

.github/workflows/ci-v2.yaml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: ['1.11.x', '1.13.x', '1.16.x', '1.18.x', '1.19.x', '1.20.x']
+        go-version: ['1.11.x', '1.13.x', '1.16.x', '1.18.x', '1.19.x', '1.20.x', '1.21.x']
     env:
       working-directory: ./v2