Chore: Move to ubuntu2004-builder

Chore: Move to ubuntu2004-builder

jjb/dcaegen2/dcaegen2-services-mapper.yaml
jjb/demo/demo.yaml
jjb/dmaap/dmaap-buscontroller.yaml
jjb/dmaap/dmaap-datarouter.yaml
jjb/dmaap/dmaap-messagerouter-dmaapclient.yaml
jjb/dmaap/dmaap-messagerouter-messageservice.yaml
jjb/externalapi/externalapi-nbi.yaml
jjb/global-defaults.yaml
jjb/holmes/holmes-common.yaml
jjb/holmes/holmes-engine-mgt.yaml
jjb/holmes/holmes-rule-mgt.yaml
jjb/integration/integration-templates.yaml
jjb/integration/integration.yaml
jjb/integration/simulators/nf-simulator/integration-simulators-nf-simulator-simulator-cli.yaml
jjb/lab/lab-templates.yaml

Issue-ID: CIMAN-33
Signed-off-by: Bengt Thuree <bthuree@linuxfoundation.org>
Change-Id: I047a44051417e27667de82c38bd016d9941ef76e