Version 1.6.0

Bugfixes:

• #100 Fixed a bug with merging PathItems where extension properties (x-*) were not present in the merge result (thanks @marcelthole)
• #131 Adjust default value for Schema::$nullable when no type is specified. nullable will be false by default when a type is specified but null when no type is specified.
• #77 Fixes default value for exclusiveMinimum and exclusiveMaximum only return false when minimum or maximum is specified, defaults to null otherwise.
• #125 Fix OpenAPI v3.0 Schema Violation: Array value found, but an object is required (thanks @om4james)
• #119 Stricter type checking when resolving references, avoid trying to call methods on array
• #144 Catch recursion when resolving inside included file

Dependencies:

• #151, #134 Add Symfony 6 support (thanks @om4csaba)

Other changes:

• Reworked CI (thanks @simPod)
• Added Docker environment for local development