Add support for encoding/decoding SMS in TPDU and SMPP format

This is important when talking OTA with a SIM.

Change-Id: I0d95e62c1e7183a7851d1fe38df0f5133830cb1f
diff --git a/setup.py b/setup.py
index d4fb15f..5678c55 100644
--- a/setup.py
+++ b/setup.py
@@ -22,6 +22,7 @@
         "colorlog",
         "pycryptodomex",
         "packaging",
+        "smpp.pdu @ git+https://github.com/hologram-io/smpp.pdu",
     ],
     scripts=[
         'pySim-prog.py',