Add EventHub test w/ Digi radio; still not working

@GArrigotti-cws, @GArrigotti, I also added `platformio.ini` files that you can use for testing on your side.

Connected to #411

examples/DRWI_DigiLTE/DRWI_DigiLTE.ino

@@ -3,6 +3,7 @@
  * @brief Example for DRWI CitSci LTE sites.
  *
  * @author Sara Geleskie Damiano <[email protected]>
+ * @author Anthony Aufdenkampe <[email protected]>
  * @copyright (c) 2017-2022 Stroud Water Research Center (SWRC)
  *                          and the EnviroDIY Development Team
  *            This example is published under the BSD-3 license.

sensor_tests/HMACEventHubTest/platformio.ini

@@ -9,10 +9,11 @@
 ; http://docs.platformio.org/page/projectconf.html
 
 [platformio]
-description = ModularSensors example intended for DRWI users with CTD, turbidity, and a EnviroDIY SIM7080G LTE modem
+description = Test HMAC & POST Requests to Event Hub API, using LTEBee (SIM27080) radio & Mayfly 1.1 
+src_dir = sensor_tests/HMACEventHubTest
 
 [env:mayfly]
-monitor_speed = 57600
+monitor_speed = 115200
 board = mayfly
 platform = atmelavr
 framework = arduino
@@ -27,9 +28,14 @@ lib_ignore =
     Adafruit TouchScreen
     Adafruit ILI9341
 build_flags =
-    -DSDI12_EXTERNAL_PCINT
+    -D SDI12_EXTERNAL_PCINT
+    -D TINY_GSM_RX_BUFFER=512
+    -D TINY_GSM_YIELD_MS=2
+    -D MS_DATAPUBLISHERBASE_DEBUG
+    -D MS_EVENTHUBPUBLISHER_DEBUG
+    ; -D TINY_GSM_DEBUG=Serial
+    ; -D MS_LOGGERMODEM_DEBUG
+    ; -D MS_DIGIXBEECELLULARTRANSPARENT_DEBUG
 lib_deps =
-    envirodiy/EnviroDIY_ModularSensors
-;  ^^ Use this when working from an official release of the library
-;    https://github.com/EnviroDIY/ModularSensors.git#develop
-;  ^^ Use this when if you want to pull from the develop branch
+    https://github.com/EnviroDIY/ModularSensors.git#hmac_auth
+;  ^^ Use this when if you want to pull from the hmac_auth feature branch