Update PIEX: Prepares support for uncompressed thumbnails

The new version of PIEX added new API for adding support to thumbnails. It also marks some old API as deprecate.

BUG=b/26894354
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1723123002

Review URL: https://codereview.chromium.org/1723123002
diff --git a/DEPS b/DEPS
index 219b347..a723d8d 100644
--- a/DEPS
+++ b/DEPS
@@ -22,7 +22,7 @@
   "third_party/externals/giflib"  : "https://android.googlesource.com/platform/external/giflib.git@ab10e256df4f684260ca239905b1cec727181f6c",
 
   "third_party/externals/dng_sdk" : "https://android.googlesource.com/platform/external/dng_sdk.git@6579353b8ee5d8aa1f1a96ae22798de9b41e19b8",
-  "third_party/externals/piex"    : "https://android.googlesource.com/platform/external/piex.git@919011b9f6fce1d9d35bf51f3aab7509f66712cc",
+  "third_party/externals/piex"    : "https://android.googlesource.com/platform/external/piex.git@883a1e5419990f51b8e928969e9c5a09869bce0e",
 
   "third_party/externals/libjpeg-turbo"             : "https://skia.googlesource.com/third_party/libjpeg-turbo.git@7bf1a3c9b06bede89cec37cec0b5085c0d6d6c13",
   # libjpeg-turbo depends on yasm to compile .asm files