Update CHANGELOG, shared object version for 3.13.0

Bug: 441135035
Change-Id: I6811273b367658627f6518b7e6fdbe43549e5d3c

CHANGELOG

diff --git a/CHANGELOG b/CHANGELOG
index 89d7a99..d0c0cab 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,4 @@
-2025-mm-dd next version
+2025-08-25 v3.13.0
   This release is ABI compatible with the last release.
 
   The aom_roi_map_t struct, used only by the codec control

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 382abf9..c7c513b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,9 +58,9 @@
 # We set SO_FILE_VERSION = [c-a].a.r
 #
 # The VERSION number in project() should be updated when these variables are.
-set(LT_CURRENT 15)
-set(LT_REVISION 1)
-set(LT_AGE 12)
+set(LT_CURRENT 16)
+set(LT_REVISION 0)
+set(LT_AGE 13)
 math(EXPR SO_VERSION "${LT_CURRENT} - ${LT_AGE}")
 set(SO_FILE_VERSION "${SO_VERSION}.${LT_AGE}.${LT_REVISION}")
 unset(LT_CURRENT)