ESP32例程编译出错问题
新建的例程，esp32编译提示错误
ninja: no work to do.
[648/923] Generating x509_crt_bundle
FAILED: esp-idf/mbedtls/x509_crt_bundle
cd /home/xx/workspace/esp32_work/http/simple/build/esp-idf/mbedtls && /home/xx/.espressif/python_env/idf4.3_py3.6_env/bin/python /home/xx/ESP_IDF/esp-idf/components/mbedtls/esp_crt_bundle/gen_crt_bundle.py --input /home/xx/ESP_IDF/esp-idf/components/mbedtls/esp_crt_bundle/cacrt_all.pem -q
gen_crt_bundle.py: Invalid certificate in /home/xx/ESP_IDF/esp-idf/components/mbedtls/esp_crt_bundle/cacrt_all.pem
Invalid certificate
ninja: build stopped: subcommand failed.
ninja failed with exit code 1
这是由于签名过期问题，关掉签名即可，进入menuconfig 或进入设置，搜索Enable trusted root certificate bundle 选项，关闭即可
关闭之后save，重新编译工程即可通过
