feat(env): added more optional env var examples (#2138)

Author: waleedlatif1

apps/sim/.env.example

@@ -14,6 +14,7 @@ NEXT_PUBLIC_APP_URL=http://localhost:3000
 # Security (Required)
 ENCRYPTION_KEY=your_encryption_key  # Use `openssl rand -hex 32` to generate, used to encrypt environment variables
 INTERNAL_API_SECRET=your_internal_api_secret # Use `openssl rand -hex 32` to generate, used to encrypt internal api routes
+API_ENCRYPTION_KEY=your_api_encryption_key # Use `openssl rand -hex 32` to generate, used to encrypt api keys
 
 # Email Provider (Optional)
 # RESEND_API_KEY=  # Uncomment and add your key from https://resend.com to send actual emails