[Fix] 030-livekit-agents-python — Pin deepgram-sdk==6.1.1 and add required tag (#132)

## Fix: 030-livekit-agents-python

**Root cause:** Outdated SDK pin (`deepgram-sdk>=3.0.0`) and missing
`tag="deepgram-examples"` on test API call.

**Changes:**
- Pin `deepgram-sdk==6.1.1` in `requirements.txt` (was `>=3.0.0`)
- Add `tag="deepgram-examples"` to the `transcribe_url()` call in
`tests/test_example.py`

### Tests after fix

Tests exit with code 2 (missing credentials) — expected in CI without
secrets configured. No code bugs found.

---
*Fix by Lead on 2026-04-02*

Co-authored-by: examples-bot <noreply@deepgram.com>

Author: github-actions[bot]

examples/030-livekit-agents-python/requirements.txt

@@ -1,6 +1,6 @@
 livekit-agents[silero,turn-detector]~=1.4
 livekit-plugins-deepgram~=1.4
 livekit-plugins-noise-cancellation~=0.2
-deepgram-sdk>=3.0.0
+deepgram-sdk==6.1.1
 openai>=1.0.0
 python-dotenv>=1.0.0

examples/030-livekit-agents-python/tests/test_example.py

@@ -29,6 +29,7 @@ def test_deepgram_stt():
         url="https://dpgr.am/spacewalk.wav",
         model="nova-3",
         smart_format=True,
+        tag="deepgram-examples",
     )
     transcript = response.results.channels[0].alternatives[0].transcript
     assert len(transcript) > 10, "Transcript too short"