Updated hackfest_multivdu_vnf: changed image from US1604 to ubuntu20.04

Updated image used in VNF to Ubuntu 20.04.

.gitlab-ci.yml

@@ -10,8 +10,10 @@ publish-repository:
     - git submodule update
     - python3 -m pip install wheel pyang pyangbind
     - git clone https://osm.etsi.org/gerrit/osm/IM.git
+    - pip3 install -r IM/requirements.txt
     - pip3 install IM/
     - git clone https://osm.etsi.org/gerrit/osm/osmclient.git
+    - pip3 install -r osmclient/requirements.txt
     - pip3 install osmclient/
     - rm -rf osmclient/ IM/
     - mv magma/* .
@@ -38,8 +40,10 @@ build-local-repository:
     - git submodule update
     - python3 -m pip install wheel pyang pyangbind
     - git clone https://osm.etsi.org/gerrit/osm/IM.git
+    - pip3 install -r IM/requirements.txt
     - pip3 install IM/
     - git clone https://osm.etsi.org/gerrit/osm/osmclient.git
+    - pip3 install -r osmclient/requirements.txt
     - pip3 install osmclient/
     - rm -rf osmclient/ IM/
     - mv magma/* .