Bump ABI version number for temporal scalability

Commit 217591f modified the encoder ABI without incrementing the version number.

Change-Id: I74de01597dadcdcd96f6b817e4ec69d9ab535e4c

vpx/vpx_encoder.h

diff --git a/vpx/vpx_encoder.h b/vpx/vpx_encoder.h
index 08219e9..87ab20c 100644
--- a/vpx/vpx_encoder.h
+++ b/vpx/vpx_encoder.h
@@ -43,7 +43,7 @@
      * types, removing or reassigning enums, adding/removing/rearranging
      * fields to structures
      */
-#define VPX_ENCODER_ABI_VERSION (2 + VPX_CODEC_ABI_VERSION) /**<\hideinitializer*/
+#define VPX_ENCODER_ABI_VERSION (3 + VPX_CODEC_ABI_VERSION) /**<\hideinitializer*/
 
 
     /*! \brief Encoder capabilities bitfield