Update README.md

README.md

 # Usage
-1. Create a token here https://gitlab.fbk.eu/-/profile/personal_access_tokens
+1. Create a token here: https://gitlab.fbk.eu/-/profile/personal_access_tokens
 2. Find the id of the project: 
+
 ![projectId](/deleteartifacts.png)
 3. Run `deleteartifact.sh` passing as first argument the `token` and second argument the `projectId`  :
     - curl -L https://gitlab.fbk.eu/fbk-scripts/deleteartifacts/-/raw/main/deleteartifacts.sh | bash -s -- token projectId