Don't use depreacted constants.

Author: Gary Gregory

src/test/java/org/apache/commons/io/FileUtilsTestCase.java

@@ -38,6 +38,7 @@
 import java.math.BigInteger;
 import java.net.URL;
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -2384,11 +2385,11 @@ public void testWriteByteArrayToFile_WithOffsetAndLength_WithAppendOptionTrue_Sh
         final File file = TestUtils.newFile(temporaryFolder, "lines.txt");
         FileUtils.writeStringToFile(file, "This line was there before you...");
 
-        final byte[] data = "SKIP_THIS_this is brand new data_AND_SKIP_THIS".getBytes(Charsets.UTF_8);
+        final byte[] data = "SKIP_THIS_this is brand new data_AND_SKIP_THIS".getBytes(StandardCharsets.UTF_8);
         FileUtils.writeByteArrayToFile(file, data, 10, 22, true);
 
         final String expected = "This line was there before you..." + "this is brand new data";
-        final String actual = FileUtils.readFileToString(file, Charsets.UTF_8);
+        final String actual = FileUtils.readFileToString(file, StandardCharsets.UTF_8);
         assertEquals(expected, actual);
     }
 
@@ -2397,11 +2398,11 @@ public void testWriteByteArrayToFile_WithOffsetAndLength_WithAppendOptionTrue_Sh
         final File file = TestUtils.newFile(temporaryFolder, "lines.txt");
         FileUtils.writeStringToFile(file, "This line was there before you...");
 
-        final byte[] data = "SKIP_THIS_this is brand new data_AND_SKIP_THIS".getBytes(Charsets.UTF_8);
+        final byte[] data = "SKIP_THIS_this is brand new data_AND_SKIP_THIS".getBytes(StandardCharsets.UTF_8);
         FileUtils.writeByteArrayToFile(file, data, 10, 22, false);
 
         final String expected = "this is brand new data";
-        final String actual = FileUtils.readFileToString(file, Charsets.UTF_8);
+        final String actual = FileUtils.readFileToString(file, StandardCharsets.UTF_8);
         assertEquals(expected, actual);
     }