gradle: bump threetenabp to 1.2.3

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

build.gradle

@@ -22,7 +22,7 @@ buildscript {
         kotlinVersion = '1.3.71'
         preferenceVersion = '1.1.0'
         streamsupportVersion = '1.7.1'
-        threetenabpVersion = '1.2.2'
+        threetenabpVersion = '1.2.3'
         // ZXING switched minSdk to 24 so we cannot upgrade to 4.0.2 without following suit.
         // If you choose to upgrade to minSDK 24 then you should also disable Jetifier from
         // gradle.properties.