docs: fix extra command in "update" instructions

readme.md

@@ -187,7 +187,7 @@ Make sure to substitute all variables for their correct values.
 1. Stop the ModShark service, if it's running: `sudo systemctl stop modshark`
 2. Log into the ModShark service account: `sudo su - modshark`
 3. Download the [latest release package](https://github.com/warriordog/ModShark/releases/latest): `wget -O ModShark-latest.zip https://github.com/warriordog/ModShark/releases/latest/download/ModShark-latest.zip`
-4. Extract the release package into your installation directory, overwriting any files: `mkdir ModShark && bsdtar -xvf ModShark-latest.zip -C ModShark`
+4. Extract the release package into your installation directory, overwriting any files: `bsdtar -xvf ModShark-latest.zip -C ModShark`
 5. Run the latest database migrations: `psql -U $postgres_user -W -d $sharkey_database -a -f ModShark/update-ModShark-migrations.sql`
 6. Return to an admin account: `exit`
 7. Start the ModShark service: `sudo systemctl start modshark`