0.8.0

• Remove support of record types - this feature was not used anywhere anyhow and made creation of validators more complex
• Add codelist directories with new root key codelists so common codelists (e.g. language tags) can be defined once in a schema and referenced at multiple places. See also https://format.gbv.de/schema/avram/specification#validation-against-a-codelist
• Add external validation rules with new key checks - see https://format.gbv.de/schema/avram/specification#external-validation-rules
• Allow deprecated-codes also at subfield schedules