Bump up encoder ABI for change to aom_codec_cx_pkt

for https://aomedia-review.googlesource.com/c/aom/+/116721

Change-Id: Ic528ad89cd92cdd6de8433de0e812b093222e898
(cherry picked from commit e50deac4e3aa1355a23647f05ec0bb6f70311c8f)

aom/aom_encoder.h

diff --git a/aom/aom_encoder.h b/aom/aom_encoder.h
index ab19f4e..a8b39ed 100644
--- a/aom/aom_encoder.h
+++ b/aom/aom_encoder.h
@@ -41,7 +41,7 @@
  * fields to structures
  */
 #define AOM_ENCODER_ABI_VERSION \
-  (8 + AOM_CODEC_ABI_VERSION) /**<\hideinitializer*/
+  (9 + AOM_CODEC_ABI_VERSION) /**<\hideinitializer*/
 
 /*! \brief Encoder capabilities bitfield
  *