Pin version of dogpile

Force dogpile to a static version as 1.0.0, released July 19, 2020
is not compatible with the version of stevedore that we use.

Change-Id: Icc2758e07bafa935bf4403bd5735b47e79b4bc66
Signed-off-by: beierlm <mark.beierl@canonical.com>
diff --git a/docker/MON/Dockerfile b/docker/MON/Dockerfile
index ce858f7..a91b957 100644
--- a/docker/MON/Dockerfile
+++ b/docker/MON/Dockerfile
@@ -42,7 +42,7 @@
 
 RUN pip3 install  'macaroonbakery>=1.1,<2.0' 'pyRFC3339>=1.0,<2.0' \
       'pyyaml>=5.1.2' 'theblues>=0.3.8,<1.0' 'websockets>=4.0,<5.0' \
-      'paramiko'   # PyNaCl
+      'paramiko' 'dogpile.cache==0.9.2'
 
 ARG REPOSITORY_BASE=http://osm-download.etsi.org/repository/osm/debian
 ARG RELEASE=ReleaseEIGHT-daily