Migrate io/ioutil uses to new APIs.

ioutil has been deprecated since Go 1.16. The functions were moved to
some combination of io and os. See https://pkg.go.dev/io/ioutil.

(File-related functions went to os. Generic things went to io. Names
were kept the same except TempDir and TempFile are os.MkdirTemp and
os.CreateTemp, respectively.)

Change-Id: I031306f69e70424841df08f64fa9d90f31780928
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/55186
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
diff --git a/util/fipstools/break-hash.go b/util/fipstools/break-hash.go
index 8c817d8..9893716 100644
--- a/util/fipstools/break-hash.go
+++ b/util/fipstools/break-hash.go
@@ -24,12 +24,11 @@
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 )
 
 func do(outPath, inPath string) error {
-	objectBytes, err := ioutil.ReadFile(inPath)
+	objectBytes, err := os.ReadFile(inPath)
 	if err != nil {
 		return err
 	}
@@ -131,7 +130,7 @@
 	fmt.Printf("\nHash of module was:          %x\n", hashWas)
 	fmt.Printf("Hash of corrupted module is: %x\n", newHash)
 
-	return ioutil.WriteFile(outPath, objectBytes, 0755)
+	return os.WriteFile(outPath, objectBytes, 0755)
 }
 
 func main() {