docs: python venv installation fix

Author: Dominick Leppich

docs/de/migration.md

@@ -11,6 +11,7 @@ Erstellen Sie zunächst eine virtuelle Python-Umgebung, aktivieren Sie diese und
 ```bash
 python3 -m venv vmenv
 . vmenv/bin/activate
+pip install wheel # This needs to be done beforehand as a separate call
 pip install requests mysql-connector-python==8.4.0 alive_progress lxml
 ```
 

docs/en/migration.md

@@ -11,6 +11,7 @@ First, create a virtual Python environment, activate it and install all required
 ```bash
 python -m venv vmenv
 . vmenv/bin/activate
+pip install wheel # This needs to be done beforehand as a separate call
 pip install requests mysql-connector-python==8.4.0 alive_progress lxml
 ```