build: update dependencies and improve test coverage

- Update base image in Dockerfile from `alpine:3.17` to `alpine:3.21`

Signed-off-by: Bo-Yi Wu <[email protected]>

Author: appleboy

docker/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.17
+FROM alpine:3.21
 
 ARG TARGETOS
 ARG TARGETARCH