added empty run statement to workaround issue moby/moby#37965

Author: darkmattercoder

Dockerfile

@@ -119,6 +119,9 @@ ENV APP_BUILDDIR=/var/build
 
 COPY --from=builder ${QT_PREFIX} ${QT_PREFIX}
 COPY --from=builder /opt/extra-dependencies/ /
+# the next copy statement failed often. My only guess is, that the extra dependencies are not existent and somehow that
+# triggers a failure here.... A workaround for similar issues is to put an empty run statement in between: https://github.com/moby/moby/issues/37965
+RUN true
 COPY entrypoint.sh ${ENTRYPOINT_DIR}
 
 RUN chmod +x ${ENTRYPOINT_DIR}/entrypoint.sh