fix(dockerfile): install abuild key (#526)

Without this, abuild refuses to run correctly.

Dockerfile

@@ -2,8 +2,9 @@ FROM alpine:3.19 AS builder-taglib
 WORKDIR /tmp
 COPY alpine/taglib/APKBUILD .
 RUN apk update && \
-    apk add --no-cache abuild && \
-    abuild-keygen -a -n && \
+    apk add --no-cache abuild doas && \
+    echo "permit nopass root" > /etc/doas.conf && \
+    abuild-keygen -a -n -i && \
     REPODEST=/pkgs abuild -F -r
 
 FROM golang:1.21-alpine AS builder