Use perl warnings pragma consistently

We've had a mixture of the warnings pragma, the -w switch on the shebang
line, and no warnings at all. This patch removes the -w swicth and add
the warnings pragma to all perl sources missing it. It raises the
severity of the TestingAndDebugging::RequireUseWarnings  perlcritic
policy to level 5, so that we catch any future violations.

Discussion: https://postgr.es/m/20200412074245.GB623763@rfd.leadboat.com

1 files changed, 1 insertions, 0 deletions

diff --git a/contrib/seg/seg-validate.pl b/contrib/seg/seg-validate.pl
index b8957ed984a..9fa0887e710 100755
--- a/contrib/seg/seg-validate.pl
+++ b/contrib/seg/seg-validate.pl
@@ -1,6 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
+use warnings;
 
 my $integer = '[+-]?[0-9]+';
 my $real    = '[+-]?[0-9]+\.[0-9]+';