Bump alpine from 3.20.2 to 3.20.3 in /linux

Bumps alpine from 3.20.2 to 3.20.3.

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

Signed-off-by: dependabot[bot] <[email protected]>

linux/Dockerfile

@@ -15,7 +15,7 @@ RUN cd /app && go get -d \
     -ldflags "-s -w -extldflags \"-static\"" \
     -o /bin/cat cat.go
 
-FROM alpine:3.20.2
+FROM alpine:3.20.3
 
 ENV LANG=C.UTF-8
 ENV SERVER_PORT=8080