Bump to v1.2.0 (#95)

* version bump for v1.2.0

* forgot to bump ABI

Author: jcupitt

meson.build

@@ -36,7 +36,7 @@ endif
 #   2. Backward-compatible ABI change: bump minor, reset patch
 #   3. Other, eg. bugfix: bump patch
 abi_version_major = 1
-abi_version_minor = 1
+abi_version_minor = 2
 abi_version_patch = 0
 
 abi_version = '@0@.@1@.@2@'.format(