Warn people about AJV's noncompliant strict mode.

Author: handrews

_data/validator-libraries-modern.yml

@@ -167,7 +167,7 @@
   implementations:
     - name: ajv
       url: https://github.com/ajv-validator/ajv
-      notes: "for Node.js and browsers - supports [user-defined keywords](https://github.com/ajv-validator/ajv/blob/master/docs/keywords.md) and [$data reference](https://github.com/json-schema-org/json-schema-spec/issues/51)"
+      notes: "for Node.js and browsers - supports [user-defined keywords](https://github.com/ajv-validator/ajv/blob/master/docs/keywords.md) and [$data reference](https://github.com/json-schema-org/json-schema-spec/issues/51); _Only specification-compliant when strict mode is **disabled.**_"
       date-draft: [2019-09, 2020-12]
       draft: [7, 6, 4]
       license: MIT