README.md: make sure we are using Thread 1.2 for all examples here

Signed-off-by: Stefan Schmidt <stefan.schmidt@huawei.com>

README.md

@@ -50,7 +50,7 @@ one will act as a Thread radio for the Linux host). This is building a sample
 that lives within the main Zephyr tree.
 
 ```
-$ west build -b arduino_nano_33_ble -- -DCONF_FILE="prj.conf overlay-rcp.conf overlay-usb-nrf-br.conf" -DDTC_OVERLAY_FILE="usb.overlay" -DCONFIG_OPENTHREAD_THREAD_VERSION_1_1=y samples/net/openthread/coprocessor/
+$ west build -b arduino_nano_33_ble -- -DCONF_FILE="prj.conf overlay-rcp.conf overlay-usb-nrf-br.conf" -DDTC_OVERLAY_FILE="usb.overlay" -DCONFIG_OPENTHREAD_THREAD_VERSION_1_2=y samples/net/openthread/coprocessor/
 $ west flash
 ```
 
@@ -73,7 +73,7 @@ longer need to worry about device names changing underneath our daemon process.
 git clone https://github.com/openthread/openthread.git
 cd openthread
 ./bootstrap
-./script/cmake-build posix -DOT_SPINEL_RESET_CONNECTION=ON -DOT_THREAD_VERSION=1.1 -DOT_DAEMON=ON
+./script/cmake-build posix -DOT_SPINEL_RESET_CONNECTION=ON -DOT_THREAD_VERSION=1.2 -DOT_DAEMON=ON
 sudo build/posix/src/posix/ot-daemon -v 'spinel+hdlc+uart:///dev/serial/by-id/usb-ZEPHYR_OpenThread_CoProcessor_NRF_E96CD39E53C49869-if00?uart-baudrate=115200&uart-reset'
 ```