Update PyElfTools as well

Fixes "ImportError: cannot import name 'MutableMapping' from 'collections'" for Python 3.10

Author: maxgerhardt

requirements.txt

@@ -14,7 +14,7 @@ mbed-ls>=1.5.1,<2.0
 mbed-host-tests>=1.4.4,<2.0
 mbed-greentea>=0.2.24,<2.0
 beautifulsoup4>=4,<=4.6.3
-pyelftools>=0.24,<=0.25
+pyelftools>=0.27,<=0.28
 pycryptodome>=3.9.3,<4
 pyusb>=1.0.0,<2.0.0
 hidapi>=0.7.99,<0.8.0;platform_system!="Linux"