application: transport_factory: update documented type of uavcan.serial.baudrate (#171)

Also bump version to 1.2.6
diff --git a/pyuavcan/VERSION b/pyuavcan/VERSION
index c813fe1..3c43790 100644
--- a/pyuavcan/VERSION
+++ b/pyuavcan/VERSION
@@ -1 +1 @@
-1.2.5
+1.2.6
diff --git a/pyuavcan/application/_transport_factory.py b/pyuavcan/application/_transport_factory.py
index ddca023..1945a26 100644
--- a/pyuavcan/application/_transport_factory.py
+++ b/pyuavcan/application/_transport_factory.py
@@ -76,7 +76,7 @@
           - Apply deterministic data loss mitigation to RPC-service transfers by setting multiplication factor = 2.
 
         * - ``uavcan.serial.baudrate``
-          - ``natural16[1]``
+          - ``natural32[1]``
           - The baudrate to set for all specified serial ports. Leave unchanged if zero.
 
     ..  list-table:: :mod:`pyuavcan.transport.can`