update reference of get-pip.py file from mongo-sidecar image (#943)

* updated get-pip.py url, added test job with make release-snapshot

* get-pip version to 3.6

* typo fixed

* using 3.5 version

* reverting unrelated changes

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

docker/kanister-mongodb-replicaset/image/install.sh

@@ -22,7 +22,7 @@ apt-get update && \
 apt-get install curl wget musl-dev python3 rsync -y
 
 echo "================= Installing Python packages ==================="
-wget --progress=dot:mega https://bootstrap.pypa.io/3.5/get-pip.py
+wget --progress=dot:mega https://bootstrap.pypa.io/pip/3.5/get-pip.py
 python3 get-pip.py
 
 echo "================= Adding awscli ============"