build(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

@@ -1,4 +1,4 @@
-FROM alpine:3.20.3 AS bin
+FROM alpine:3.21.0 AS bin
 
 ARG TARGETOS
 ARG TARGETARCH
@@ -19,7 +19,7 @@ RUN set -ex \
     esac \
   && cp /dist/kured_${TARGETOS}_${TARGETARCH}${SUFFIX}/kured /dist/kured;
 
-FROM alpine:3.20.3
+FROM alpine:3.21.0
 RUN apk update --no-cache && apk upgrade --no-cache && apk add --no-cache ca-certificates tzdata
 COPY --from=bin /dist/kured /usr/bin/kured
 ENTRYPOINT ["/usr/bin/kured"]