Update perl to v5.30 to fix OCI image manifest version

More context: Perl/docker-perl#161

Author: 89Q12

.github/workflows/perl.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         perl-version:
-          - '5.20'
+          - '5.30'
           - 'latest'
           - 'threaded'