infra: Force a given docker architecture.

See https://github.com/docker-library/official-images/issues/3835

Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>
diff --git a/Dockerfile b/Dockerfile
index a254495..e3d36de 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,5 +8,5 @@
 RUN find /source/database -mindepth 1 -maxdepth 1 -type d -exec /source/htmlgen/htmlgen.py --settings={}/settings.sh --output=/output/html \;
 RUN mkdir -p /output/raw && find /source/database -mindepth 1 -maxdepth 1 -type d -exec cp -R {} /output/raw \;
 
-FROM nginx:alpine
+FROM amd64/nginx:latest
 COPY --from=db_builder /output /usr/share/nginx/html