chore : fix Dockerfile to use fully qualified image name

+ Update Dockerfile to use fully qualified base image name with registry prefix in
  order to be used by podman.
+ Update runner image to use Red Hat UBI9 image
+ Replace Entrypoint instruction to use exec form instead of shell form

Signed-off-by: Rohan Kumar <rohaan@redhat.com>

Author: rohanKanojia

images/builder/Dockerfile

@@ -1,16 +1,16 @@
 # Build the manager binary
 # FROM registry.access.redhat.com/ubi8/go-toolset:1.17.7 as builder
-FROM golang:1.18 as builder
+FROM registry.access.redhat.com/ubi9/go-toolset:1.22.9-1743094161 AS builder
 
 USER root
 WORKDIR /workspace
 COPY . .
 RUN make build
 
-FROM registry.access.redhat.com/ubi8/ubi-minimal
+FROM registry.access.redhat.com/ubi9/ubi-minimal:9.5-1742914212
 
-LABEL MAINTAINER "Adrian Riobo" "<ariobolo@redhat.com>"
+LABEL MAINTAINER="Adrian Riobo <ariobolo@redhat.com>"
 
 COPY --from=builder /workspace/out/eventmanager /workspace/images/builder/entrypoint.sh /usr/local/bin/
 
-ENTRYPOINT entrypoint.sh 
+ENTRYPOINT ["entrypoint.sh"]