build(deps): bump alpine from 3.20.1 to 3.20.2 in /frpc

Bumps alpine from 3.20.1 to 3.20.2.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

frpc/Dockerfile

@@ -4,7 +4,7 @@
 # https://github.com/fatedier/frp
 
 # Build environment
-FROM alpine:3.20.1 AS build 
+FROM alpine:3.20.2 AS build 
 ARG TARGETOS
 ARG TARGETARCH
 ARG FRP_VERSION