README: Fix eventfilter url

It's case sensitive

Change-Id: I3e27924833345a6956cf4b10839357e11a2145fc
Reviewed-on: https://codereview.kdab.com/c/kdab/KDToolBox/+/81139
Reviewed-by: Mike Krus <mike.krus@kdab.com>
Tested-by: Continuous Integration <build@kdab.com>

README.md

@@ -21,7 +21,7 @@ Tools
   A proxy model flattening a table model into a list model (mainly for Qt Quick 2).
 - [TabWindow widget](https://github.com/KDAB/KDToolBox/tree/master/qt/tabWindow)
   A tab widget that allows extracting a tab to a new window, like modern web browsers.
-- [EventFilter](https://github.com/KDAB/KDToolBox/tree/master/qt/eventFilter)
+- [EventFilter](https://github.com/KDAB/KDToolBox/tree/master/qt/eventfilter)
   A way for "connecting" a QEvent to lambda with two lines of code.
 - [MessageHandler](https://github.com/KDAB/KDToolBox/tree/master/qt/messagehandler)
   An API to help you intercept the output going through qDebug()/qWarning()/etc.