libcmatrix 0.0.2

wlroots nicely collects breaking API changes. We should do the same:

Breaking changes

CmMatrix

• Don't expose cmatrix_data_dir, cmatrix_app_id (!89 (merged)). The client passes them to CmMatrix so knows them anyway.
• Don't try to migrate old chatty accounts to the new secrets schema (!87 (merged))
• cm_matrix_save_client_async and cm_matrix_delete_client_async now take a GCancellable like other async methods (!87 (merged))

CmClient

• Renamed cm_client_join_room_by_id_async() to cm_client_join_room_async() and cm_client_join_room_by_id_finish() to cm_client_join_room_finish() (!88 (merged)). They allow joining by room-id or a room alias.
• The ordering of the arguments to CmCallback changed to better match other callbacks (!66 (merged))