chore: update README with environmental variables

Author: AndreaGiulianelli

README.md

@@ -2,5 +2,11 @@
 This is the repository of the Automation Management microservice of the Smart Operating Block project.
 
 ## Usage
-Define the following environment variables:
+You need to specify the following environment variable:
+- `AZURE_CLIENT_ID`: ID of an Azure AD application
+- `AZURE_TENANT_ID`: ID of the application's Azure AD tenant
+- `AZURE_CLIENT_SECRET`: the application's client secrets
+- `AZURE_DT_ENDPOINT`: the Azure Digital Twins instance endpoint
+- `BOOTSTRAP_SERVER_URL`: the kafka connection endpoint
 - `CONFIG_PATH`: the path where the microservice can find the configuration for environmental data and automation scenarios.
+- `SCHEMA_REGISTRY_URL`: the schema registry url