Dockerfile: bump alpine to 3.16

Signed-off-by: Maisem Ali <maisem@tailscale.com>

Dockerfile.base

@@ -2,5 +2,5 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-FROM alpine:3.15
+FROM alpine:3.16
 RUN apk add --no-cache ca-certificates iptables iproute2 ip6tables

build_docker.sh

@@ -25,7 +25,7 @@ export PATH=$PWD/tool:$PATH
 eval $(./build_dist.sh shellvars)
 DEFAULT_TAGS="v${VERSION_SHORT},v${VERSION_MINOR}"
 DEFAULT_REPOS="tailscale/tailscale,ghcr.io/tailscale/tailscale"
-DEFAULT_BASE="ghcr.io/tailscale/alpine-base:3.14"
+DEFAULT_BASE="ghcr.io/tailscale/alpine-base:3.16"
 
 PUSH="${PUSH:-false}"
 REPOS="${REPOS:-${DEFAULT_REPOS}}"