Release v0.23.0

What's Changed

• Pin Poetry version to 1.8 by @dc-almeida in #450
• Remove redundant illegal character check attribute by @dc-almeida in #452
• Rename NUTS hierarchy by @dc-almeida in #455
• Filter mappings from external repo by @phackstock in #460
• Remove None defaults from RegionAggregationMapping by @phackstock in #466
• Add from_external_repository attribute to Code by @dc-almeida in #459
• Specify illegal character(s) found and respective attribute(s) by @dc-almeida in #456
• Refactor multiple warning levels for same data validation filter by @dc-almeida in #461
• Check if constituents of common regions are in native regions by @dc-almeida in #463
• Update citation by @dc-almeida in #472

Full Changelog: v0.22.1...v0.23.0