README: correct the image suffix

Now the built image is with `.wic` suffix only.

Signed-off-by: Baocheng Su <[email protected]>

README.md

@@ -30,7 +30,7 @@ Then open the menu to select the desired image and options:
 After the build completed, the final image is under
 
 ```text
-build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic.img
+build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic
 ```
 
 ## Build user SDK
@@ -69,14 +69,14 @@ Under Linux, insert an unused SD card. Assuming the SD card takes device
 /dev/mmcblk0, use dd to copy the image to it. For example:
 
 ```shell
-$ sudo dd if=build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic.img \
+$ sudo dd if=build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic \
           of=/dev/mmcblk0 bs=4M oflag=sync
 ```
 
 Alternatively, install the bmap-tools package and run the following command which is generally faster and safer:
 
 ```shell
-$ sudo bmaptool copy build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic.img /dev/mmcblk0
+$ sudo bmaptool copy build/tmp/deploy/images/iot2050/iot2050-image-example-iot2050-debian-iot2050.wic /dev/mmcblk0
 ```
 
 The example image starts with the IP 192.168.200.1 preconfigured on the first
@@ -134,7 +134,7 @@ It is possible to create an image with a SWUpdate based
 ./kas-container build kas-iot2050-example.yml:kas/opt/swupdate-example.yml
 ```
 
-You can find the final image under `build/tmp/deploy/images/iot2050/iot2050-image-swu-example-iot2050-debian-iot2050.wic.img`. This image holds the necessary partition layout with two root file systems. The image `iot2050-image-swu-example-iot2050-debian-iot2050.wic.img` can be flashed directly to a SD card as described in section [Booting the image from SD card](#booting-the-image-from-sd-card).
+You can find the final image under `build/tmp/deploy/images/iot2050/iot2050-image-swu-example-iot2050-debian-iot2050.wic`. This image holds the necessary partition layout with two root file systems. The image `iot2050-image-swu-example-iot2050-debian-iot2050.wic` can be flashed directly to a SD card as described in section [Booting the image from SD card](#booting-the-image-from-sd-card).
 
 NOTE: As the image contains 2 root file systems, it has a size of 7 Gigabytes.