fix: update GitHub Actions to v6 and Go to 1.23

- Update docker/build-push-action from v5 to v6 to fix Node.js 20 deprecation warning
- Update Go version from 1.21 to 1.23 in Dockerfile
- Add go mod verify after go mod download for better error handling

.github/workflows/docker-build.yml

@@ -49,7 +49,7 @@ jobs:
             type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21-alpine AS builder
+FROM golang:1.23-alpine AS builder
 
 WORKDIR /app
 
@@ -6,7 +6,7 @@ WORKDIR /app
 ENV GOPROXY=https://goproxy.cn,direct
 
 COPY go.mod go.sum ./
-RUN go mod download
+RUN go mod download && go mod verify
 
 COPY . .
 RUN CGO_ENABLED=0 GOOS=linux go build -o zai-proxy .