Add very basic "perl-cpanm" test

test/config.sh

@@ -169,6 +169,7 @@ imageTests+=(
 	'
 	[perl]='
 		perl-hello-world
+		perl-cpanm
 	'
 	[php]='
 		php-ext-install

test/tests/perl-cpanm/container.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+set -eux
+
+cpanm --notest Mojolicious

test/tests/perl-cpanm/run.sh

@@ -0,0 +1 @@
+../run-sh-in-container.sh