Resolver: Fix the build.

Some packages are now available in the community repo for 3.20 so
there's no need for the edge community repo (and it breaks the build).

resolver/Dockerfile

 FROM alpine:3.20
 # hadolint ignore=DL3018
 RUN echo '@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing' >> /etc/apk/repositories && \
-    echo '@community http://dl-cdn.alpinelinux.org/alpine/edge/community' >> /etc/apk/repositories && \
     apk add --update --no-cache \
         bash \
-        dma@testing \
+        dma \
         gosu@testing \
         iproute2 \
-        knot-resolver@community \
+        knot-resolver \
         knot-utils \
         mailx \
         mtr \