perl-gdgraph: add license hash

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/perl-gdgraph/perl-gdgraph.hash

@@ -1,3 +1,6 @@
 # retrieved by scancpan from http://cpan.metacpan.org/
 md5    38c6a188519e6272e9b2b722b315c3d8 GDGraph-1.54.tar.gz
 sha256 b96f5c10b656c17d16ab65a1777c908297b028d3b6815f6d54b2337f006bfa4f GDGraph-1.54.tar.gz
+
+# computed by scancpan
+sha256 710484e3a1196664bbe8a5ad5d53c528e01226eb20e2885a4e1131eb6c6565cd Dustismo.LICENSE