fix: add requirements.txt and update readme (#109)

As an alternative to uncommenting this line in`pyproject.toml`:
```
...
#"google-generativeai == 0.7.2",
...
```

slack_support/README.md

@@ -62,3 +62,6 @@ You are ready to roll. Deploy your project:
 ```
 $ ak deploy --project slack_support --dir .
 ```
+
+> [!NOTE]
+> This project includes a `requirements.txt` file for installing dependencies. This is relevant when using the [cloud offering](https://app.autokitteh.cloud/) or when running in [Docker mode](https://docs.autokitteh.com/get_started/start_server/#docker). If you're not using Google Gemini and want to customize this project, you can remove or modify the file as needed. Otherwise, leave it as is.

slack_support/main.py

@@ -56,7 +56,7 @@ def send(text):
         msg = autokitteh.next_event(s, timeout=60)
 
         if not msg:  # timeout
-            dt = datetime.now().total_seconds() - start_time.total_seconds()
+            dt = (datetime.now() - start_time).total_seconds()
             print(f"timeout, dt={dt}")
 
             if not taken_by and dt >= HELP_REQUEST_TIMEOUT_MINUTES * 60:

slack_support/requirements.txt

@@ -0,0 +1 @@
+google-generativeai==0.8.3