fix: schema property:example should be validated (#375)

* fix: schema property:example should be validated
* chore: schema-example separate rule
* test: example-schema: string, number, int
* chore: example object in schema test + minor rule fix
* chore: support v3.1.0
* chore: rewrite schema-example-type rule using ajv
* update tests for 3.1
* chore: no-invalid-parameter-examples rule
* fix: reporting
* chore: added disallowAdditionalProperties
* docs: rules no-invalid parameter & schema examples

__tests__/lint/no-invalid-schema-examples-array-error/snapshot.js

@@ -0,0 +1,28 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`E2E lint no-invalid-schema-examples-array-error 1`] = `
+
+validating /openapi.yaml...
+[1] openapi.yaml:34:21 at #/paths/~1my_post/post/requestBody/content/application~1json/schema/properties/my_list/example
+
+Example value must conform to the schema: type must be array.
+
+32 |               type: string
+33 |             example:
+34 |               test
+   |               ^^^^
+35 | responses:
+36 |   '200':
+
+referenced from openapi.yaml:29:19
+
+Error was generated by the no-invalid-schema-examples rule.
+
+
+/openapi.yaml: validated in <test>ms
+
+❌ Validation failed with 1 error.
+run \`openapi lint --generate-ignore-file\` to add all problems to the ignore file.
+
+
+`;