chore: Upgrade UBI base image to 8.8 (kserve#121)

Vulnerabities fixed:
- [RHSA-2023:7165] cups security and bug fix update (Moderate)
- [RHSA-2023:7151] python3 security update (Moderate)
- [RHSA-2023:7176] python-pip security update (Moderate)
- [RHSA-2023:7151] python3 security update (Moderate)
- [RHSA-2023:7190] avahi security update (Moderate)
- [RHSA-2023:7112] shadow-utils security and bug fix update (Low)

-----

Signed-off-by: Spolti <[email protected]>

Author: spolti

Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM registry.access.redhat.com/ubi8/ubi-minimal:8.6 as build_base
+FROM registry.access.redhat.com/ubi8/ubi-minimal:8.8 as build_base
 
 # https://docs.docker.com/engine/reference/builder/#automatic-platform-args-in-the-global-scope
 # don't provide "default" values (e.g. 'ARG TARGETARCH=amd64') for non-buildx environments,