Update requirements.txt

Add an upper bound to the API version of pyusb.

Co-Authored-By: c1728p9 <[email protected]>

Author: bridadan

requirements.txt

@@ -22,4 +22,4 @@ pyelftools>=0.24,<=0.25
 git+https://github.com/armmbed/[email protected]
 icetea>=1.2.1,<1.3
 pycryptodome>=3.7.2,<=3.7.3
-pyusb>=1.0.0
+pyusb>=1.0.0,<2.0.0