[#38] signature: Increase pool max object size

According to the results of profiling, objects with a size of 72KB
are mainly allocated.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

util/signature/buffer.go

@@ -2,7 +2,7 @@ package signature
 
 import "sync"
 
-const poolSliceMaxSize = 64 * 1024
+const poolSliceMaxSize = 128 * 1024
 
 type buffer struct {
 	data []byte