Update CHANGELOG.md for v0.1.0b6 release (microsoft#139)

Add changelog entry for v0.1.0b6 covering PRs microsoft#115, microsoft#117, microsoft#126, microsoft#137

Co-authored-by: Abel Milash <abelmilash@microsoft.com>

Author: abelmilash-msft

CHANGELOG.md

@@ -5,6 +5,18 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.1.0b6] - 2026-03-12
+
+### Added
+- Context manager support: `with DataverseClient(...) as client:` for automatic resource cleanup, HTTP connection pooling, and `close()` for explicit lifecycle management (#117)
+- Typed return models `Record`, `TableInfo`, and `ColumnInfo` for record and table metadata operations, replacing raw `Dict[str, Any]` returns with full backward compatibility (`result["key"]` still works) (#115)
+- Alternate key management: `client.tables.create_alternate_key()`, `client.tables.get_alternate_keys()`, `client.tables.delete_alternate_key()` with typed `AlternateKeyInfo` model (#126)
+
+### Fixed
+- `@odata.bind` lookup bindings now preserve navigation property casing (e.g., `new_CustomerId@odata.bind`), fixing `400 Bad Request` errors on create/update/upsert with lookup fields (#137)
+- Reduced unnecessary HTTP round-trips on create/update/upsert when records contain `@odata.bind` keys (#137)
+- Single-record `get()` now lowercases `$select` column names consistently with multi-record queries (#137)
+
 ## [0.1.0b5] - 2026-02-27
 
 ### Fixed
@@ -70,6 +82,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Comprehensive error handling with specific exception types (`DataverseError`, `AuthenticationError`, etc.) (#22, #24)
 - HTTP retry logic with exponential backoff for resilient operations (#72)
 
+[0.1.0b6]: https://github.com/microsoft/PowerPlatform-DataverseClient-Python/compare/v0.1.0b5...v0.1.0b6
 [0.1.0b5]: https://github.com/microsoft/PowerPlatform-DataverseClient-Python/compare/v0.1.0b4...v0.1.0b5
 [0.1.0b4]: https://github.com/microsoft/PowerPlatform-DataverseClient-Python/compare/v0.1.0b3...v0.1.0b4
 [0.1.0b3]: https://github.com/microsoft/PowerPlatform-DataverseClient-Python/compare/v0.1.0b2...v0.1.0b3