tests/kola: switch container helpers to Fedora 43

This should have been part of 51a217a1a2
but there was a failure observed in the
`ext.config.podman.rootless-systemd` test that wasn't seen using the
Fedora 42 container images. There must have been some update with either
systemd, selinux-policy, coreos-assembler, or elsewhere that allows
httpd to start in a rootless-systemd environment again becasue the test
is now passing.

tests/kola/data/commonlib.sh

@@ -24,13 +24,13 @@ get_ipv4_for_nic() {
 
 get_fedora_container_ref() {
     local repo='quay.io/fedora/fedora'
-    local tag='42'
+    local tag='43'
     echo "${repo}:${tag}"
 }
 
 get_fedora_minimal_container_ref() {
     local repo='quay.io/fedora/fedora-minimal'
-    local tag='42'
+    local tag='43'
     echo "${repo}:${tag}"
 }