chore(main): release 7.5.0 (#743)

Release PR for **7.5.0** — [compare
v7.4.0...v7.5.0](https://github.com/deepgram/deepgram-python-sdk/compare/v7.4.0...v7.5.0)

## What's in 7.5.0

- **[#742](https://github.com/deepgram/deepgram-python-sdk/pull/742) —
Flux TTS streaming (Speak V2) + agent listen reconfigure**
- **Speak V2 streaming (WebSocket)** — `client.speak.v2.connect(...)`:
new `speak/v2/` package (client, socket client, request/response types),
top-level `SpeakV2Encoding` / `SpeakV2MipOptOut` / `SpeakV2Model` /
`SpeakV2SampleRate` / `SpeakV2Tag`, and optional `send_flush()` /
`send_close()` control messages.
- **Agent mid-session listen reconfigure** — `send_update_listen(...)`
with `AgentV1UpdateListen` / `AgentV1UpdateListenListen`, plus the
`AgentV1ListenUpdated` server acknowledgement.
- **Flux end-of-turn tuning** — new listen-provider fields
`eot_threshold`, `eager_eot_threshold`, `eot_timeout_ms`.

- **[#744](https://github.com/deepgram/deepgram-python-sdk/pull/744) —
Flux TTS batch (REST) + agent latency report**
- **Speak V2 batch (REST)** — `client.speak.v2.audio.generate(...)` (+
raw client): the REST companion to streaming. `model` required
(flux-only); optional `encoding` / `container` / `sample_rate` /
`bit_rate` / `callback` / `callback_method` / `tag` / `mip_opt_out` /
`priority`. No `speed` (GA-only, excluded for EA).
- `sample_rate` / `bit_rate` are typed as `int` — a float like `24000.0`
is rejected on the wire.
- Callback mode returns the `SpeakV2AcceptedResponse` JSON ack through
the audio byte iterator as raw bytes; join the chunks and parse
`request_id` yourself (documented in the docstring; typed content-type
dispatch tracked as a follow-up).
- **`AgentV1LatencyReport`** — new latency-report type + request, wired
into the agent socket-client response union.
- **Agent inject-message `interrupt`** — new value on
`AgentV1InjectAgentMessageBehavior`.

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please).

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Greg Holmes <greg.holmes@deepgram.com>