images: upgrade to Alpine 3.18 (#9997)

Alpine Linux 3.18 was released
https://alpinelinux.org/posts/Alpine-3.18.0-released.html

Signed-off-by: Jintao Zhang <zhangjintao9020@gmail.com>

images/nginx/rootfs/Dockerfile

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-FROM alpine:3.17.2 as builder
+FROM alpine:3.18.0 as builder
 
 COPY . /
 
@@ -21,7 +21,7 @@ RUN apk update \
   && /build.sh
 
 # Use a multi-stage build
-FROM alpine:3.17.2
+FROM alpine:3.18.0
 
 ENV PATH=$PATH:/usr/local/luajit/bin:/usr/local/nginx/sbin:/usr/local/nginx/bin