Chore: Move to centos8-builder

Chore: Move to centos8-builder

jjb/integration/docker/integration-docker-onap-python.yaml
jjb/integration/simulators/integration-5G-core-nf-simulator.yaml
jjb/integration/simulators/integration-A1-policy-enforcement-simulator.yaml
jjb/integration/simulators/integration-core-nssmf-simulator.yaml
jjb/integration/simulators/integration-pnf-simulator.yaml
jjb/integration/simulators/integration-ran-nssmf-simulator.yaml
jjb/integration/simulators/integration-ran-simulator.yaml
jjb/integration/simulators/nf-simulator/integration-pm-https-server-nf-simulator.yaml
jjb/integration/simulators/nf-simulator/integration-simulators-nf-simulator-avcn-manager.yaml
jjb/integration/simulators/nf-simulator/integration-simulators-nf-simulator-netconf-server.yaml

Issue-ID: CIMAN-33
Signed-off-by: Bengt Thuree <bthuree@linuxfoundation.org>
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
Change-Id: I3981d42f723bf3fb91687c37c2dd2ca905bbd4ae
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>