Use #!/usr/bin/env perl

Instead of using the hardcoded /usr/bin/perl executable, use
/usr/bin/env perl, so the perlbrew version could be ran.

lib/Dancer2/Cookbook.pod

@@ -18,7 +18,7 @@ Dancer2 has been designed to be easy to work with - it's trivial to write a
 simple web app, but still has the power to work with larger projects. To
 start with, let's make an incredibly simple "Hello World" example:
 
-    #!/usr/bin/perl
+    #!/usr/bin/env perl
 
     use Dancer2;
 

script/dancer2

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 # PODNAME: dancer2
 # ABSTRACT: Dancer2 command line interface
 

t/psgi_app_forward_and_pass.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 use strict;
 use warnings;
 

t/template_tiny/01_compile.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use strict;
 

t/template_tiny/02_trivial.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use strict;
 

t/template_tiny/03_samples.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use strict;
 

t/template_tiny/04_compat.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use strict;
 

t/template_tiny/05_preparse.t

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 use strict;