'HTTP_HEAD' isn't declared in HTTPMethod

[ZakCodes]

Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: ESP-12
• Core Version: adfc28d
• Development Env: Arduino IDE (1.8.9)
• Operating System: ArchLinux

Settings in IDE

• Module: NodeMCU 1.0
• Flash Mode: dio (I believe)
• Flash Size: 4MB
• lwip Variant: v2 Lower Memory
• Reset Method: nodemcu (RTS pin)
• Flash Frequency: 40Mhz
• CPU Frequency: 160MHz
• Upload Using: SERIAL
• Upload Speed: 115200

Problem Description

The HTTP HEAD method isn't part of the HTTPMethod enum in the ESP8266WebServer library.

MCVE Sketch

#include <Arduino.h>
#include <ESP8266WebServer.h>

void setup() {
    HTTPMethod get = HTTP_GET; // Good
    HTTPMethod head = HTTP_HEAD; // Doesn't exist
}

void loop() {

}

Debug Messages

sketch_aug11a:5:23: error: 'HTTP_HEAD' was not declared in this scope
     HTTPMethod head = HTTP_HEAD;
                       ^
Using library ESP8266WebServer at version 1.0 in folder: /home/zakcodes/.arduino15/packages/esp8266/hardware/esp8266/2.5.2/libraries/ESP8266WebServer 
Using library ESP8266WiFi at version 1.0 in folder: /home/zakcodes/.arduino15/packages/esp8266/hardware/esp8266/2.5.2/libraries/ESP8266WiFi 
exit status 1
'HTTP_HEAD' was not declared in this scope