add API version test in GitLab::API

GitLab/API.pm

@@ -22,7 +22,7 @@ use GitLab::API::Iterator;
 
 use parent "Exporter";
 
-our $VERSION = 8.12.1;
+our $VERSION = 10.2.4;
 
 my %defaults = (
     per_page        => 50,
@@ -49,6 +49,15 @@ sub new {
         $args{URL} = "$s://$args{Host}/api/v$v";
     }
 
+    my ($req_version) = ($args{URL} =~ m!api/v(\d+)!);
+    if (!defined $req_version) {
+        carp "Cannot determine requested version of API";
+    } elsif ($req_version < 4) {
+        carp "API version $req_version is deprecated";
+    } elsif ($req_version > 4) {
+        croak "API version $req_version is not supported";
+    }
+
     $log->debug("initializing GitLab::API for \"$args{URL}\"");
 
     my $self = {