Return None instead of raising an exception on missing, valid emeter keys (#146)

Fixes #142

Also, update the pre-commit hooks to their newest versions

devtools/parse_pcap.py

@@ -8,6 +8,7 @@ from pprint import pprint as pp
 import click
 import dpkt
 from dpkt.ethernet import ETH_TYPE_IP, Ethernet
+
 from kasa.protocol import TPLinkSmartHomeProtocol