docs(readme): fix chmod in deb installation instructions

Signed-off-by: Sandro-Alessio Gierens <sandro@gierens.de>

README.md

@@ -105,7 +105,7 @@ To install eza from this repo use:
 sudo mkdir -p /etc/apt/keyrings
 wget -qO- https://raw.githubusercontent.com/eza-community/eza/main/deb.asc | sudo gpg --dearmor -o /etc/apt/keyrings/gierens.gpg
 echo "deb [signed-by=/etc/apt/keyrings/gierens.gpg] http://deb.gierens.de stable main" | sudo tee /etc/apt/sources.list.d/gierens.list
-sudo chmod o+r /etc/apt/keyrings/gierens.gpg /etc/apt/sources.list.d/gierens.list
+sudo chmod 644 /etc/apt/keyrings/gierens.gpg /etc/apt/sources.list.d/gierens.list
 sudo apt update
 sudo apt install -y eza
 ```