perl-plack: re-indent Config.in help text

Fixes the following check-package warning:

package/perl-plack/Config.in:18: help text: <tab><2 spaces><62 chars> (http://nightly.buildroot.org/#writing-rules-config-in)

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/perl-plack/Config.in

@@ -15,6 +15,7 @@ config BR2_PACKAGE_PERL_PLACK
 	select BR2_PACKAGE_PERL_URI
 	select BR2_PACKAGE_PERL_WWW_FORM_URLENCODED
 	help
-	  Perl Superglue for Web frameworks and Web Servers (PSGI toolkit)
+	  Perl Superglue for Web frameworks and Web Servers (PSGI
+	  toolkit)
 
 	  https://github.com/plack/Plack