✨ Add support for OpenAPI 3.1.0 (#9770)

✨ Add support for OpenAPI 3.1.0 (#9770)

* ✨ Update OpenAPI models for JSON Schema 2020-12 and OpenAPI 3.1.0

* ✨ Add support for summary and webhooks

* ✨ Update JSON Schema for UploadFiles

* ⏪️ Revert making paths optional, to ensure always correctness

* ⏪️ Keep UploadFile as format: binary for compatibility with the rest of Pydantic bytes fields in v1

* ✨ Update version of OpenAPI generated to 3.1.0

* ✨ Update the version of Swagger UI

* 📝 Update docs about extending OpenAPI

* 📝 Update docs and links to refer to OpenAPI 3.1.0

* ✨ Update logic for handling webhooks

* ♻️ Update parameter functions and classes, deprecate example and make examples the main field

* ✅ Update tests for OpenAPI 3.1.0

* 📝 Update examples for OpenAPI metadata

* ✅ Add and update tests for OpenAPI metadata

* 📝 Add source example for webhooks

* 📝 Update docs for metadata

* 📝 Update docs for Schema extra

* 📝 Add docs for webhooks

* 🔧 Add webhooks docs to MkDocs

* ✅ Update tests for extending OpenAPI

* ✅ Add tests for webhooks

* ♻️ Refactor generation of OpenAPI and JSON Schema with params

* 📝 Update source examples for field examples

* ✅ Update tests for examples

* ➕ Make sure the minimum version of typing-extensions installed has deprecated() (already a dependency of Pydantic)

* ✏️ Fix typo in Webhooks example code

* 🔥 Remove commented out code of removed nullable field

* 🗑️ Add deprecation warnings for example argument

* ✅ Update tests to check for deprecation warnings

* ✅ Add test for webhooks with security schemes, for coverage

* 🍱 Update image for metadata, with new summary

* 🍱 Add docs image for Webhooks

* 📝 Update docs for webhooks, add docs UI image