update xx to v1.6.1 for compatibility with alpine 3.21 and file 5.46+

This fixes compatibility with alpine 3.21 and file 5.46+

- Fix additional possible `xx-cc`/`xx-cargo` compatibility issue with Alpine 3.21
- Support for Alpine 3.21
- Fix `xx-verify` with `file` 5.46+
- Fix possible error taking lock in `xx-apk` in latest Alpine without `coreutils`

full diff: tonistiigi/xx@v1.2.1...v1.6.1

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Dockerfile

@@ -2,7 +2,7 @@
 
 ARG GO_VERSION=1.23.2
 ARG ALPINE_VERSION=3.20
-ARG XX_VERSION=1.2.1
+ARG XX_VERSION=1.6.1
 
 FROM --platform=$BUILDPLATFORM tonistiigi/xx:${XX_VERSION} AS xx
 FROM --platform=$BUILDPLATFORM golang:${GO_VERSION}-alpine${ALPINE_VERSION} AS base