Update minimum Perl version to 5.16.0 and add missing 'warnings'

[tgreenx]

Purpose

This PR updates Zonemaster-Engine modules which were missing either a minimum Perl version or the warnings Perl library.

Moreover, the minimum Perl version is raised from 5.14.2 to 5.16.0 to match our current documentation.

As a drive-by change, this also fixes a variable declaration error from #1341.

Context

Spotted while fixing #1341

How to test this PR

Check that no Zonemaster-Engine Perl modules are missing these libraries:

cd zonemaster-engine/
find lib -type f -name '*.pm' \( -exec grep -q '^use warnings;$' '{}' \; -or -print \)
find lib -type f -name '*.pm' \( -exec grep -q '^use v5.16.0;$' '{}' \; -or -print \)

Note that with this change, other errors have started to show and will be fixed in another PR: #1343

[marc-vanderwal]

I suggest an alternative test procedure:

In the root of Zonemaster::Engine’s code repository, run the following command:

find lib -type f -name '*.pm' \( -exec grep -q '^use warnings;$' '{}' \; -or -print \)

Expect no output. Files that appear are missing a use warnings; line.

[marc-vanderwal]

I see that a test in t/Test.t is now failing, but this definitely seems to be a bug uncovered by the use of use warnings;. Not a regression, but simply a latent problem waiting to be fixed.

[tgreenx]

I suggest an alternative test procedure:

In the root of Zonemaster::Engine’s code repository, run the following command:

find lib -type f -name '*.pm' \( -exec grep -q '^use warnings;$' '{}' \; -or -print \)

Expect no output. Files that appear are missing a use warnings; line.

Thanks. I added it to the test procedure.

I see that a test in t/Test.t is now failing, but this definitely seems to be a bug uncovered by the use of use warnings;. Not a regression, but simply a latent problem waiting to be fixed.

Yes, this is fixed in another PR: #1343

[mattias-p]

I checked https://perldoc.perl.org/feature#FEATURE-BUNDLES and AFAICT the bump from 5.14 to 5.16 shouldn't break anything.

[matsduf]

@tgreenx, can you check this? Will rebasing solve the test issue?

[tgreenx]

As previously stated, the errors generated by this PR are fixed in #1343. We decided to merge them together.

[matsduf]

Release testing for v2024.1

I have verified in the code, but I have no installation of Perl v5.15 or lower to test with, but I do not think it is needed.