docker(deps): bump alpine from 3.20.3 to 3.21.0

Bumps alpine from 3.20.3 to 3.21.0.

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

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

Dockerfile

@@ -7,7 +7,7 @@ RUN go mod download
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o gofihttpbin ./cmd/gofihttpbin/gofihttpbin.go
 
 
-from alpine:3.20.3
+from alpine:3.21.0
 
 WORKDIR /gofihttpbin
 RUN mkdir -p ./web/static