vmtests: bump LVH rhel8 kernel image to rhel8.9

A kernel bug fails to trigger the BPF program hooked on a tracepoint if
the binary name passed as parameter is long enough, you can trigger it
with a long path, using mtardy/pathgen for example and bpftrace:

bpftrace -e 'tracepoint:sched:sched_process_exec { printf("execute\n"); }'

Under rhel8.6, if the path is long enough (>3000 for example), the BPF
prog will not be triggered.

Signed-off-by: Mahe Tardy <[email protected]>

.github/workflows/vmtests.yml

@@ -67,7 +67,7 @@ jobs:
         matrix:
            kernel:
               # renovate: datasource=docker depName=quay.io/lvh-images/kernel-images
-              - 'rhel8-20240620.102250'
+              - 'rhel8.9-20240806.173325'
               # renovate: datasource=docker depName=quay.io/lvh-images/kernel-images
               - 'bpf-next-20240624.013140'
               # renovate: datasource=docker depName=quay.io/lvh-images/kernel-images