fix: support vuex > 3.6.2

[MaxLeiter]

🐛 The bug
I'm using Vuex 4.0.2 with typed-vuex 0.3.0 and all works well except for this message when I run yarn:
warning " > typed-vuex@0.3.0" has incorrect peer dependency "vuex@^3.6.2".

🛠️ To reproduce
Steps to reproduce the behavior:

1. yarn add typed-vuex@latest vuex@latest
2. read the output

🌈 Expected behaviour
no warning should be produced

ℹ️ Additional context