Move to latest release of minio-go (#4886)

- Region handling can now use region endpoints directly.
- All uploads are streaming no more large buffer needed.
- Major API overhaul for CopyObject(dst, src)
- Fixes bugs present in existing code for copying
  - metadata replace directive CopyObject
  - PutObjectPart doesn't require md5Sum and sha256

cmd/gateway-s3_test.go

@@ -15,3 +15,44 @@
  */
 
 package cmd
+
+import (
+	"testing"
+)
+
+// Tests extracting md5/sha256 bytes.
+func TestGetMD5AndSha256Bytes(t *testing.T) {
+	testCases := []struct {
+		md5Hex    string
+		sha256Hex string
+		success   bool
+	}{
+		// Test 1: Hex encoding failure.
+		{
+			md5Hex:    "a",
+			sha256Hex: "b",
+			success:   false,
+		},
+		// Test 2: Hex encoding success.
+		{
+			md5Hex:    "91be0b892e47ede9de06aac14ca0369e",
+			sha256Hex: "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			success:   true,
+		},
+		// Test 3: hex values are empty should return success.
+		{
+			md5Hex:    "",
+			sha256Hex: "",
+			success:   true,
+		},
+	}
+	for i, testCase := range testCases {
+		_, _, err := getMD5AndSha256SumBytes(testCase.md5Hex, testCase.sha256Hex)
+		if err != nil && testCase.success {
+			t.Errorf("Test %d: Expected success, but got failure %s", i+1, err)
+		}
+		if err == nil && !testCase.success {
+			t.Errorf("Test %d: Expected failure, but got success", i+1)
+		}
+	}
+}