htslib: add libdeflate as a build dependency

From the htslib INSTALL page:
'libdeflate (optional, but strongly recommended for faster gzip)'
(https://github.com/samtools/htslib/blob/acc28ac1e52efcdd9a06706aaf0021e1082ef1ba/INSTALL#L41C1-L41C68)

Using libdeflate significantly speeds up tabix query operations.

pkgs/by-name/ht/htslib/package.nix

@@ -7,6 +7,7 @@
   bzip2,
   xz,
   curl,
+  libdeflate,
   perl,
 }:
 
@@ -34,6 +35,7 @@ stdenv.mkDerivation (finalAttrs: {
     bzip2
     xz
     curl
+    libdeflate
   ];
 
   configureFlags =