pmb.chroot.apk_static: use sha256 sig for verification

Fixes #2456
Depends on https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/72741

pmb/chroot/apk_static.py

@@ -88,7 +88,7 @@ def verify_signature(files, sigkey_path):
             [
                 "openssl",
                 "dgst",
-                "-sha1",
+                "-sha256",
                 "-verify",
                 sigkey_path,
                 "-signature",