Update to shim-15.8
    
    Resolves: CVE-2023-40546
    Resolves: CVE-2023-40547
    Resolves: CVE-2023-40548
    Resolves: CVE-2023-40549
    Resolves: CVE-2023-40550
    Resolves: CVE-2023-40551
    Resolves: rhbz#2113005
    Resolves: rhbz#2189197
    Resolves: rhbz#2238884
    Resolves: rhbz#2259264
    
    Signed-off-by: Peter Jones <pjones@redhat.com>