default to deploying dspo's main tag

I noticed when deploying DSPO by pointing a kfdef at this repository,
I get a month-old version of DSPO. When I do the same for dashboard,
I get main. We might as well default to main too ... if someone is
pointing at DSPO or building it from source, they probably want
bleeding edge anyway.

Author: gregsheremeta

config/base/params.env

@@ -5,5 +5,5 @@ IMAGES_SCHEDULEDWORKFLOW=quay.io/opendatahub/ds-pipelines-scheduledworkflow:main
 IMAGES_CACHE=registry.access.redhat.com/ubi8/ubi-minimal
 IMAGES_MOVERESULTSIMAGE=registry.access.redhat.com/ubi8/ubi-micro
 IMAGES_MARIADB=registry.redhat.io/rhel8/mariadb-103:1-188
-IMAGES_DSPO=quay.io/opendatahub/data-science-pipelines-operator:main-d9ee12b
+IMAGES_DSPO=quay.io/opendatahub/data-science-pipelines-operator:main
 IMAGES_OAUTHPROXY=registry.redhat.io/openshift4/ose-oauth-proxy:v4.12.0