Use HTPPS Endpoints

[airgradienthq]

Endpoint hw.airgradient.com supports HTTPS.

We should switch all endpoints to HTTPS.

[pnt325]

@airgradienthq
I have success connect to hw.airgradient.com success on ESP32C3. ESP8266 unable connected to with the same way self-signed certificate. I'm run the original example code BearSSL_Validation.ino

DebugLog

13:13:43.572 -> It is also possible to accept *any* self-signed certificate.  This is
13:13:43.572 -> absolutely insecure as anyone can make a self-signed certificate.
13:13:43.572 -> First, try and connect to a badssl.com self-signed website (will fail):
13:13:43.572 -> Trying: self-signed.badssl.com:443...*** Can't connect. ***
13:13:58.588 -> -------
13:13:58.588 -> Now we'll enable self-signed certs (will pass)
13:13:58.634 -> Trying: hw.airgradient.com:443...*** Can't connect. ***
13:13:59.459 -> -------