Change BSSL_CertStore test URL (#7370)

github.com forwards to www.github.com
So reaching out for "www.github.com" returns HTTP 304 instead of the nice HTTP 204

Author: kinafu

libraries/ESP8266WiFi/examples/BearSSL_CertStore/BearSSL_CertStore.ino

@@ -148,8 +148,8 @@ void setup() {
   BearSSL::WiFiClientSecure *bear = new BearSSL::WiFiClientSecure();
   // Integrate the cert store with this connection
   bear->setCertStore(&certStore);
-  Serial.printf("Attempting to fetch https://www.github.com/...\n");
-  fetchURL(bear, "www.github.com", 443, "/");
+  Serial.printf("Attempting to fetch https://github.com/...\n");
+  fetchURL(bear, "github.com", 443, "/");
   delete bear;
 }