Update Dockerfile

Author: sachin-pikle

samples/imagedims-python/Dockerfile

@@ -7,6 +7,7 @@ RUN pip3 install --target /python/  --no-cache --no-cache-dir -r requirements.tx
   chmod -R o+r /python
 ADD . /function/
 RUN rm -fr /function/.pip_cache
+
 FROM fnproject/python:3.6
 RUN microdnf install oracle-epel-release-el8 &&\
       microdnf install ImageMagick &&\