Adds test vectors for credentials (#79)

* Promote test-vectors from web5-kt to sdk-development.

* lint

* modify linter

* try updating the linter again

* Final lint

.markdownlint-cli2.yaml

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 config:
   line-length: false
+  no-duplicate-heading:
+    siblings_only: true

web5-test-vectors/credentials/README.md

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+# `credentials` Test Vectors
+
+This directory contains test vectors for the `credentials` module. It's important to note that the test vectors ensure
+that
+the implementations are following the [Verifiable Credential 1.1 specification](https://www.w3.org/TR/vc-data-model/).
+
+## `create`
+
+Create test vectors are available for [success](./create_success.json) and [failure](./create_failure.json) test cases.
+
+### Input
+
+The value of `input` is an object with the following properties.
+
+| Property           | Description                                                                                                              |
+|--------------------|--------------------------------------------------------------------------------------------------------------------------|
+| `signerDidUri`     | the did uri that will be used to sign the verifiable credential created.                                                 |
+| `signerPrivateJwk` | Json Web Key object associated with the `signerDidUri` which will be used for signing `credential`.                      |
+| `credential`       | A JSON object that represents a Verifiable Credential 1.1 according to the [spec](https://www.w3.org/TR/vc-data-model/). |
+
+### Output
+
+The value of `output` is a Verifiable Credential 1.1 encoded as a JSON Web Token (
+see [here](https://www.w3.org/TR/vc-data-model/#json-web-token) for more details). The signature is created using
+the `signerPrivateJwk` private key.
+
+### Reference implementations
+
+The reference implementations for:
+
+* `create_success` can be
+  found [here](https://github.com/TBD54566975/web5-kt/blob/466e8d8ca9771ae3a98767e5a4a79ac7b1e7a5d8/credentials/src/test/kotlin/web5/sdk/credentials/VerifiableCredentialTest.kt#L244).
+* `create_failure` can be
+  found [here](https://github.com/TBD54566975/web5-kt/blob/466e8d8ca9771ae3a98767e5a4a79ac7b1e7a5d8/credentials/src/test/kotlin/web5/sdk/credentials/VerifiableCredentialTest.kt#L285).
+
+## `verify`
+
+Verify test vectors are available for [success](./verify_success.json) and [failure](./verify_failure.json) test cases.
+
+### Input
+
+The value of `input` is an object with the single property `vcJwt`. The value of `vcJwt` is a Verifiable Credential 1.1
+encoded as a JSON Web Token (see [here](https://www.w3.org/TR/vc-data-model/#json-web-token) for more details).
+
+### Output
+
+Output is empty, signalling that no exception nor errors should be thrown for success cases. For failure cases, the
+`errors` property is set to `true`, signalling that an exception or an error should be returned or thrown.
+
+### Reference implementations
+
+The reference implementations for:
+
+* `verify_success` can be
+  found [here](https://github.com/TBD54566975/web5-kt/blob/466e8d8ca9771ae3a98767e5a4a79ac7b1e7a5d8/credentials/src/test/kotlin/web5/sdk/credentials/VerifiableCredentialTest.kt#L261).
+* `verify_failure` can be
+  found [here](https://github.com/TBD54566975/web5-kt/blob/466e8d8ca9771ae3a98767e5a4a79ac7b1e7a5d8/credentials/src/test/kotlin/web5/sdk/credentials/VerifiableCredentialTest.kt#L273).