Adding tzdata to container

To be able to set a timezone inside a container with the env variable TZ
the tzdata package is needed. Otherwise only UTC will be set.

docker/armv7/Dockerfile.alpine

@@ -88,6 +88,7 @@ RUN [ "cross-build-start" ]
 RUN mkdir /data \
     && apk add --no-cache \
         openssl \
+        tzdata \
         curl \
         dumb-init \
         ca-certificates