update test data

gtars/tests/data/chroms.meta.bed

@@ -1,24 +1,24 @@
-chr1	0	248956422	1
-chr2	0	242193529	1
-chr3	0	198295559	2
-chr4	0	190214555	2
-chr5	0	181538259	3
-chr6	0	170805979	3
-chr7	0	159345973	4
-chr8	0	145138636	4
-chr9	0	138394717	5
-chr10	0	133797422	5
-chr11	0	135086622	6
-chr12	0	133275309	6
-chr13	0	114364328	6
-chr14	0	107043718	7
-chr15	0	101991189	7
-chr16	0	90338345	8
-chr17	0	83257441	8
-chr18	0	80373285	8
-chr19	0	58617616	8
-chr20	0	64444167	9
-chr21	0	46709983	9
-chr22	0	50818468	10
-chrX	0	156040895	11
-chrY	0	57227415	11
+chr1	0	248956422	cluster_1
+chr2	0	242193529	cluster_1
+chr3	0	198295559	cluster_2
+chr4	0	190214555	cluster_2
+chr5	0	181538259	cluster_3
+chr6	0	170805979	cluster_3
+chr7	0	159345973	cluster_4
+chr8	0	145138636	cluster_4
+chr9	0	138394717	cluster_5
+chr10	0	133797422	cluster_5
+chr11	0	135086622	cluster_6
+chr12	0	133275309	cluster_6
+chr13	0	114364328	cluster_6
+chr14	0	107043718	cluster_7
+chr15	0	101991189	cluster_7
+chr16	0	90338345	cluster_8
+chr17	0	83257441	cluster_8
+chr18	0	80373285	cluster_8
+chr19	0	58617616	cluster_8
+chr20	0	64444167	cluster_9
+chr21	0	46709983	cluster_9
+chr22	0	50818468	cluster_10
+chrX	0	156040895	cluster_11
+chrY	0	57227415	cluster_11