Update ajv from 8.11.0 to 8.12.0

[legobeat]

Updates pinned dependency ajv to latest.

Release Notes 8.12.0:

• fix JTD serialisation (remove leading comma in objects with only optional properties) (remove leading comma in JTD serialisation result, fixes #2001, fixes #2171, fixes #2181 ajv-validator/ajv#2190, @piliugin-anton)
• empty JTD "values" schema (JTD empty values schema, fixes #1949 ajv-validator/ajv#2191)
• empty object to work with JTD utility type (special case empty object for jtd ajv-validator/ajv#2158, @erikbrinkman)
• fix JTD "discriminator" schema for objects with more than 8 properties (fix JTD discriminator with more than 8 properties, fixes #1971 ajv-validator/ajv#2194)
• correctly narrow "number" type to "integer" (correctly narrow "number" type to "integer", fixes #1935 ajv-validator/ajv#2192, @JacobLey)

Release Notes 8.11.2:

Update dependencies
Export ValidationError and MissingRefError (ajv-validator/ajv#1840, @dannyb648)

8.11.1 was pre-release of 8.11.2

Diffs

Source diff `v8.12.0...v8.11.0

Package diff `ajv@8.12.0...ajv@8.11.0

[legobeat]

Closing in favor of #796 (changed branch name to conform with contributing guidelines)