ci: add dynamic Go version selection for CI testing

- Enable testing across Go 1.24 and 1.25 using a matrix strategy
- Update the container image to dynamically use the selected Go version

Signed-off-by: appleboy <appleboy.tw@gmail.com>

.github/workflows/testing.yml

@@ -30,8 +30,11 @@ jobs:
 
   testing:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go-version: ["1.24", "1.25"]
     container:
-      image: golang:1.23-alpine
+      image: golang:${{ matrix.go-version }}-alpine
       options: --sysctl net.ipv6.conf.all.disable_ipv6=0
     steps:
       - name: Checkout repository