modify style of READEME.md of ota_demo

(cherry-picked from commit 2a0ecb5)

Signed-off-by: Hyundo Lee <54927573+hdlee27@users.noreply.github.com>

Author: hdlee27

apps/esp32/ota_demo/README.md

@@ -10,7 +10,7 @@ Because this application is based on _switch_example_ . you could find more deta
 
 Change configuration
 -------------------
-These compile options will enable HTTPS and MBEDTLS feature to connect OTA server.
+These compile options will enable HTTPS and MBEDTLS feature to connect OTA server.   
 `stdkconfig`
 ```c
 // Enable option for HTTPS
@@ -26,7 +26,7 @@ CONFIG_STDK_IOT_CORE_NET_MBEDTLS=y
 
 Import certificate
 -------------------
-This application requires _root.pem_, _public_key.pem_ which is used for https connection and firmware signature validation.
+This application requires _root.pem_, _public_key.pem_ which is used for https connection and firmware signature validation.   
 You can find how to create these file from [here](../../../doc/ota_demo.md#preparing-certificate)
 
 ```sh
@@ -38,7 +38,7 @@ $ cp public_key.pem [st-device-sdk-c-ref path]/apps/esp32/ota_demo/main
 
 Register capability callback
 -------------------
-This code init handle and add command callback for **Firmware Update** capability.
+This code init handle and add command callback for **Firmware Update** capability.   
 `main.c`
 ```c
 // create ota data for capability
@@ -51,7 +51,7 @@ cap_ota_data->cmd_update_firmware_usr_cb = cap_update_cmd_cb;
 
 Send currentVersion
 -------------------
-This code will update `currentVersion` attribute by sending event.
+This code will update `currentVersion` attribute by sending event.   
 `main.c`
 ```c
 char *firmware_version = get_current_firmware_version();
@@ -62,7 +62,7 @@ cap_ota_data->set_currentVersion(cap_ota_data, firmware_version);
 
 Lookup available new firmware
 -----------------------------
-This code will lookup available new firmware by reading OTA server's `versioninfo.json` and send `availableVersion` event.
+This code will lookup available new firmware by reading OTA server's `versioninfo.json` and send `availableVersion` event.   
 `main.c`
 ```c
 
@@ -95,7 +95,7 @@ void ota_check_for_update(void *user_data)
 
 Run firmware update
 -------------------
-This code will run firmware update by receiving `updateFirmware` command.
+This code will run firmware update by receiving `updateFirmware` command.   
 `main.c`
 ```c
 static void ota_update_task(void * pvParameter)