Remove shipped antispam plugin binary, related to #33

dovecot/Dockerfile

@@ -5,6 +5,7 @@ RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/re
      dovecot \
      dovecot-sqlite \
      dovecot-pigeonhole-plugin \
+     dovecot-antispam-plugin@testing \
      rspamd-client@testing \
      bash \
  && rm -rf /var/cache/apk/*
@@ -12,9 +13,6 @@ RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/re
 COPY dovecot-pigeonhole-plugin-extdata-39-r0.apk /
 RUN apk add --allow-untrusted --force dovecot-pigeonhole-plugin-extdata-39-r0.apk
 
-COPY dovecot-antispam-plugin-51-r0.apk /
-RUN apk add --allow-untrusted --force dovecot-antispam-plugin-51-r0.apk
-
 COPY conf /etc/dovecot
 COPY sieve /var/lib/dovecot