Merge branch 'feature/http_client_head' into 'master'

esp_http_client: add head method support

See merge request idf/esp-idf!2895

diff --cc components/esp_http_client/esp_http_client.c
Simple merge

diff --cc components/esp_http_client/include/esp_http_client.h
Simple merge

diff --cc examples/protocols/esp_http_client/main/esp_http_client_example.c
Simple merge