Fix SpotBugs issues in DelegateFileFilter

- [ERROR] Medium: Class
org.apache.commons.io.filefilter.DelegateFileFilter defines
non-transient non-serializable instance field fileFilter
[org.apache.commons.io.filefilter.DelegateFileFilter] In
DelegateFileFilter.java SE_BAD_FIELD
- [ERROR] Medium: Class
org.apache.commons.io.filefilter.DelegateFileFilter defines
non-transient non-serializable instance field fileNameFilter
[org.apache.commons.io.filefilter.DelegateFileFilter] In
DelegateFileFilter.java SE_BAD_FIELD

Author: garydgregory

src/changes/changes.xml

@@ -53,6 +53,8 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" due-to="Stephan Markwalder, Gary Gregory">Add test for FileChannels.contentEquals() #509.</action>
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix FileChannels.contentEquals().</action>
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix some Javadoc issues in LineIterator and IOUtils.</action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.filefilter.DelegateFileFilter defines non-transient non-serializable instance field fileFilter [org.apache.commons.io.filefilter.DelegateFileFilter] In DelegateFileFilter.java SE_BAD_FIELD.</action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.filefilter.DelegateFileFilter defines non-transient non-serializable instance field fileNameFilter [org.apache.commons.io.filefilter.DelegateFileFilter] In DelegateFileFilter.java SE_BAD_FIELD.</action>
       <!-- UPDATE -->
       <action dev="ggregory" type="update" due-to="Gary Gregory">Bump org.codehaus.mojo:exec-maven-plugin from 3.1.0 to 3.1.1 #512.</action>
       <action dev="ggregory" type="update" due-to="Gary Gregory">Bump commons-lang3 from 3.13.0 to 3.14.0.</action>      

src/main/java/org/apache/commons/io/filefilter/DelegateFileFilter.java

@@ -38,9 +38,9 @@ public class DelegateFileFilter extends AbstractFileFilter implements Serializab
     private static final long serialVersionUID = -8723373124984771318L;
 
     /** The File filter */
-    private final FileFilter fileFilter;
+    private transient final FileFilter fileFilter;
     /** The Filename filter */
-    private final FilenameFilter fileNameFilter;
+    private transient final FilenameFilter fileNameFilter;
 
     /**
      * Constructs a delegate file filter around an existing FileFilter.