replace all "crypto/sha256" with "github.com/minio/sha256-simd" (#5391)

This change replaces all imports of "crypto/sha256" with
"github.com/minio/sha256-simd". The sha256-simd package
is faster on ARM64 (NEON instructions) and can take advantage
of AVX-512 in certain scenarios.

Fixes #5374

pkg/hash/reader.go

@@ -19,12 +19,13 @@ package hash
 import (
 	"bytes"
 	"crypto/md5"
-	"crypto/sha256"
 	"encoding/base64"
 	"encoding/hex"
 	"errors"
 	"hash"
 	"io"
+
+	sha256 "github.com/minio/sha256-simd"
 )
 
 var errNestedReader = errors.New("Nesting of Reader detected, not allowed")

pkg/madmin/utils.go

@@ -18,7 +18,6 @@ package madmin
 
 import (
 	"crypto/md5"
-	"crypto/sha256"
 	"encoding/xml"
 	"io"
 	"io/ioutil"
@@ -27,6 +26,8 @@ import (
 	"net/url"
 	"strings"
 
+	sha256 "github.com/minio/sha256-simd"
+
 	"github.com/minio/minio-go/pkg/s3utils"
 )