fix+update dockerfile

Author: Robert Sachunsky

Dockerfile

@@ -1,4 +1,4 @@
-FROM ocrd/core:latest AS base
+FROM ocrd/core:v2.67.2 AS base
 ARG VCS_REF
 ARG BUILD_DATE
 LABEL \
@@ -7,10 +7,11 @@ LABEL \
     org.label-schema.vcs-url="https://github.com/OCR-D/ocrd_cis" \
     org.label-schema.build-date=$BUILD_DATE
 
-ENV VERSION="Di 12. Mai 13:26:35 CEST 2020"
 ENV GITURL="https://github.com/cisocrgroup"
 ENV DOWNLOAD_URL="http://cis.lmu.de/~finkf"
 
+SHELL ["/bin/bash", "-c"]
+
 # deps
 RUN apt-get update \
 	&& apt-get -y install --no-install-recommends locales