update changelog with new bug fixes and features for 5.4.0

sdk/CHANGELOG.md

@@ -1,11 +1,14 @@
 card.io Android SDK change log and release notes
 ================================================
 
-5.3.5
+5.4.0
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+* Add ability to blur all digits in the scanned card image, minus any number of digits to remain unblurred, enabled via `CardIOActivity.EXTRA_UNBLUR_DIGITS`.   (Thank you Michael Schmoock!)
+* Fix issue where Maestro cards were not correctly recognized [#154](https://github.com/card-io/card.io-Android-SDK/issues/154).
 * Fix issue on Android 23 and above where `CardIOActivity#canReadCardWithCamera()` would return the incorrect value if permissions had not been granted [#136](https://github.com/card-io/card.io-Android-SDK/issues/136).  Now defaults to `true` in such cases.
 * Add missing locales to javadocs [card.io-Android-source#75](https://github.com/card-io/card.io-Android-source/issues/75).
 * Upgrade gradle to 2.13.
+* Upgrade Android Gradle plugin to 2.1.0.
 
 5.3.4
 -----