feat: Update zephyr example to v4.0.0

V4.0.0 release of zephyr is used to build the example, as
older versions had issues with building the example. Zephyr SDK and
toolchain are also updated to v0.17.0 This commit also updates
the README file to reflect the changes.

.gitlab-ci.yml

@@ -17,9 +17,9 @@ variables:
   ARM_TOOLCHAIN_URL: https://developer.arm.com/-/media/Files/downloads/gnu/13.2.rel1/binrel/arm-gnu-toolchain-13.2.rel1-x86_64-arm-none-eabi.tar.xz?rev=e434b9ea4afc4ed7998329566b764309&hash=CA590209F5774EE1C96E6450E14A3E26
   QEMU_PATH: /opt/qemu/bin/qemu-system-xtensa
   ZEPHYR_REPO: https://github.com/zephyrproject-rtos/zephyr.git
-  ZEPHYR_REPO_REV: v3.5.0
-  ZEPHYR_TOOLCHAIN: https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.16.3/toolchain_linux-x86_64_xtensa-espressif_esp32_zephyr-elf.tar.xz
-  ZEPHYR_SDK: https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.16.3/zephyr-sdk-0.16.3_linux-aarch64_minimal.tar.xz
+  ZEPHYR_REPO_REV: v4.0.0
+  ZEPHYR_TOOLCHAIN: https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.17.0/toolchain_linux-x86_64_xtensa-espressif_esp32_zephyr-elf.tar.xz
+  ZEPHYR_SDK: https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.17.0/zephyr-sdk-0.17.0_linux-aarch64_minimal.tar.xz
   PI_PICO_SDK_REV: 1.5.1
   PI_PICO_SDK: https://github.com/raspberrypi/pico-sdk
 
@@ -186,7 +186,7 @@ build_zephyr:
     - unset IDF_PATH
     - west zephyr-export
     - west update hal_espressif
-    - west build -p -b esp32_devkitc_wroom $CI_PROJECT_DIR/examples/zephyr_example -DZEPHYR_EXTRA_MODULES=$CI_PROJECT_DIR
+    - west build -p -b esp32_devkitc_wroom/esp32/procpu $CI_PROJECT_DIR/examples/zephyr_example -DZEPHYR_EXTRA_MODULES=$CI_PROJECT_DIR
 
 build_pi_pico:
   stage: build

examples/common/example_common.c

@@ -345,7 +345,6 @@ esp_loader_error_t flash_binary(const uint8_t *bin, size_t size, size_t address)
 
         int progress = (int)(((float)written / binary_size) * 100);
         printf("\rProgress: %d %%", progress);
-        fflush(stdout);
     };
 
     printf("\nFinished programming\n");