chore(deps): update alpine docker tag to v3.21.3 (#191)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Dockerfile

@@ -1,6 +1,6 @@
 FROM busybox:1.37.0-uclibc@sha256:f1a295688a1cad4f66e7f45484a882a8b45fbdea28fa0a889ac17146775ad1a2 as busybox
 
-FROM alpine:3.21.2@sha256:56fa17d2a7e7f168a043a2712e63aed1f8543aeafdcee47c58dcffe38ed51099 as cloudflared
+FROM alpine:3.21.3@sha256:a8560b36e8b8210634f77d9f7f9efd7ffa463e380b75e2e74aff4511df3ef88c as cloudflared
 
 # Dockerfile cross compilation helper
 FROM tonistiigi/xx@sha256:923441d7c25f1e2eb5789f82d987693c47b8ed987c4ab3b075d6ed2b5d6779a3 AS xx