make static methods in Error final (#204)

[Server][Conformance] Kicking off adoption of conformance testing (#181)

make sure StdioTransport does not break BC for 0.2.1 (#201)

* make sure StdioTransport does not break BC for 0.2.1

* fix phpstan baseline

Add changelog for 0.2.0 (#187)

Make logger nullable in Transport constructors (#152)

- BaseTransport: Accept ?LoggerInterface parameter and convert null to NullLogger
- StdioTransport: Change logger parameter to nullable
- StreamableHttpTransport: Change logger parameter to nullable
- InMemoryTransport: Fix missing parent::__construct() call and add logging