Update commons-parent from 48 to 49.

This should fix Java >= 11 builds on Travis due to use of source option
on Javadoc invocations.

Author: Gary Gregory

pom.xml

@@ -19,7 +19,7 @@
   <parent>
     <groupId>org.apache.commons</groupId>
     <artifactId>commons-parent</artifactId>
-    <version>48</version>
+    <version>49</version>
   </parent>
   <modelVersion>4.0.0</modelVersion>
   <groupId>commons-io</groupId>