added what's new info

WHATSNEW.md

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+# What's new #
+
+## Version 2.2 ##
+
+  * Replaced Venus GPS 634FLPx (sparkfun #9133) with newer 638FLPx (sparkfun #11058). The unfortunate pinout reshuffling in the newer part makes version 2.2 of the tracker incompatible with the older part.
+  * Eagle 6.x is required
+  * Use Arduino's own 5V regulator
+  * Replaced TO220 3.3V regulator with SMT + board sink
+  * Added bleeder resistor for passive piezo speakers
+
+## Version 2.1 ##
+
+  * Support for active piezo buzzers
+  * Auto 3.3/5.0v operation for Chipkit Uno32 compatibility
+  * Battery voltage sensing
+
+## Version 1.0 ##
+
+  * This is a reduced version of the previous board, contributed by Kyle Crockett. As opposed to the stand-alone version, this a daughter board (shield) that plugs on Arduinos.
+  * MX146 support has been removed
+