Add missing @test

Author: garydgregory

src/test/java/org/apache/commons/codec/binary/Base64Test.java

@@ -308,6 +308,7 @@ void testCodec112() { // size calculation assumes always chunked
     /**
      * Tests <a href="https://issues.apache.org/jira/browse/CODEC-263">CODEC-263</a>.
      */
+    @Test
     public void testCodec263() {
       Base64.decodeBase64("publishMessage");
       assertTrue(Base64.isBase64("publishMessage"));