feat: add mvp 'make verify' to verify signatures on current digests

Makefile

@@ -36,6 +36,10 @@ compat:
 preseed:
 	./src/preseed.sh
 
+.PHONY: verify
+verify:
+	./src/verify.sh
+
 .PHONY: digests
 digests:
 	./src/digests.sh

src/verify.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+set -eu
+
+for each in $( \
+    cat digests.txt \
+    | sed 's/\([a-z0-9]\+\) \(.*\)/signatures\/stagex\/\2@sha256=\1/g' \
+); do
+    echo $each;
+    for sig in $(find $each -type f); do
+        cat $sig | /usr/bin/gpg -v 2>&1 > /dev/null \
+            | grep "Good signature" || :
+    done;
+done