MT#61800 perl: Switch code to «use v5.40»

This will make available several new language features.

Change-Id: Ib95203a159051bea6ef443d87d6d70645c35379d

Build.PL

@@ -8,6 +8,7 @@ my $builder = Module::Build->new(
     dist_author       => 'Kirill Solomko <ksolomko@sipwise.com>',
     dist_version_from => 'lib/NGCP/Cleanup.pm',
     requires          => {
+        perl        => '5.040',
     },
 );
 $builder->create_build_script;

lib/NGCP/Cleanup.pm

@@ -1,7 +1,7 @@
 package NGCP::Cleanup;
 
-use strict;
-use warnings;
+use v5.40;
+
 use English;
 use DBI;
 use DateTime;

ngcp-cleanup-acc

@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
-use strict;
-use warnings;
+use v5.40;
+
 use NGCP::Cleanup;
 
 my $config_file = '/etc/ngcp-cleanup-tools/acc-cleanup.conf';

ngcp-cleanup-cdr-files

@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
-use strict;
-use warnings;
+use v5.40;
+
 use Config::Any;
 use File::Find;
 

ngcp-cleanup-sems

@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
-use strict;
-use warnings;
+use v5.40;
+
 use Redis;
 
 my $max_days = 2;