build: bump dso version for 1.5.3

Changes to the AES checking are technically an ABI change, although it
is not expected that any user will be affected.

Author: jgriffiths

src/Makefile.am

@@ -199,11 +199,11 @@ libwallycore_la_INCLUDES = \
 
 if SHARED_BUILD_ENABLED
 # Increment at every ABI change (whether breaking or non-breaking)
-LT_VER_CURRENT = 8
+LT_VER_CURRENT = 9
 # Increment at every release, but reset to 0 at every ABI change
 LT_VER_REVISION = 0
 # Increment at every ABI change, but reset to 0 if breaking
-LT_VER_AGE = 2
+LT_VER_AGE = 3
 # The library filename will be "libwallycore.so.$((current-age)).$((age)).$((revision))",
 # and the soname will be "libwallycore.so.$((current-age))".
 # Do NOT try to make the library version-info follow the project release version number!