bump to Rocky9

Dockerfile

@@ -1,16 +1,16 @@
-FROM --platform=$TARGETPLATFORM rockylinux:8.9
+FROM --platform=$TARGETPLATFORM rockylinux/rockylinux:9.4
 
 # Define args and set a default value
 ARG maintainer=tier
 ARG imagename=shibboleth_sp
 ARG version=3.4.1
-ARG TIERVERSION=20240308-Rocky8-MA
+ARG TIERVERSION=20240515-Rocky9-MA
 
 MAINTAINER $maintainer
 LABEL Vendor="Internet2"
 LABEL ImageType="Base"
 LABEL ImageName=$imagename
-LABEL ImageOS=rocky8
+LABEL ImageOS=rocky9
 LABEL Version=$version
 
 LABEL Build docker build --rm --tag $maintainer/$imagename .