Declare httpx[http2] dependency in requirements

[mweinelt]

Please read the contributing guidelines and the AI policy before submitting a PR. Every PR must be read and submitted by a person, and PRs that appear to be unreviewed AI output will be closed without review.

Proposed change

Declare explicit dependency on httpx[http2] in requirements-wheel.txt. There are various consumers of httpx, but it has not been explicitly tracked as a dependency. Folds in the install of the Debian python3-h2 package into requiremennts.txt style declaration.

$ rg -l httpx frigate
frigate/api/camera.py
frigate/genai/plugins/llama_cpp.py
frigate/genai/plugins/ollama.py
frigate/genai/plugins/openai.py
frigate/test/test_genai_providers.py

I think it currently leaks in via google-genaiand openai fwiw.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code
• Documentation Update

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to discussion with maintainers (required for any large or "planned" features):

For new features

• There is an existing feature request or discussion with community interest for this change.
  • Link:

AI disclosure

• No AI tools were used in this PR.
• AI tools were used in this PR. Details below:

AI tool(s) used (e.g., Claude, Copilot, ChatGPT, Cursor):

How AI was used (e.g., code generation, code review, debugging, documentation):

Extent of AI involvement (e.g., generated entire implementation, assisted with specific functions, suggested fixes):

Human oversight: Describe what manual review, testing, and validation you performed on the AI-generated portions.

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I can explain every line of code in this PR if asked.
• UI changes including text have used i18n keys and have been added to the en locale.
• The code has been formatted using Ruff (ruff format frigate)