updates samtools to 1.21

[bwlang]

FOR CONTRIBUTOR:

• I have read the CONTRIBUTING.md document and this tool is appropriate for the tools-iuc repo.
• License permits unrestricted use (educational + commercial)
• This PR adds a new tool or tool collection
• This PR updates an existing tool or tool collection
• This PR does something else (explain below)

[bgruening]

 r000	99	insert	50	30	10M	=	80	30	ATTTAGCTAC	AAAAAAAAAA	RG:Z:cow	PG:Z:bull
@@ -45,10 +45,10 @@
 x11	0	ref2*HLA:1a:2:b	12	30	24M	*	0	0	AATAATTAAGTCTACAGAGCAACT	????????????????????????	RG:Z:cow-[2]	PG:Z:bull-3A2CCEF5
 x6	0	ref2*HLA:1a:2:b	14	30	23M	*	0	0	TAATTAAGTCTACAGAGCAACTA	???????????????????????	RG:Z:cow
 x12	0	ref2*HLA:1a:2:b	14	30	23M	*	0	0	TAATTAAGTCTACAGAGCAACTA	???????????????????????	RG:Z:cow-[2]	PG:Z:bull-3A2CCEF5
-r005	163	ref1	7	30	8M4I4M1D3M	=	37	39	TTAGATAAAGAGGATACTG	*	XX:B:S,12561,2,20,112	YY:i:100	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65
-r006	0	ref1	9	30	1S2I6M1P1I1P1I4M2I	*	0	0	AAAAGATAAGGGATAAA	*	XA:Z:abc	XB:i:-10	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65
-r007	0	ref1	9	30	5H6M	*	0	0	AGCTAA	*	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65
-r007	0	ref1	16	30	6M14N1I5M	*	0	0	ATAGCTCTCAGC	*	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65
-r006	16	ref1	29	30	6H5M	*	0	0	TAGGC	*	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65
-r005	83	ref1	37	30	9M	=	7	-39	CAGCGCCAT	*	RG:Z:colt-55424A4	PG:Z:donkey-6ADB4A65

This result for BAM merge looks suspicious. Is that ok?