Get a commit

Gets a Git [commit object](https://git-scm.com/book/en/v1/Git-Internals-Git-Objects#Commit-Objects). **Signature verification object** The response will include a `verification` object that describes the result of verifying the commit's signature. The following fields are included in the `verification` object: | Name | Type | Description | | ---- | ---- | ----------- | | `verified` | `boolean` | Indicates whether GitHub considers the signature in this commit to be verified. | | `reason` | `string` | The reason for verified value. Possible values and their meanings are enumerated in table below. | | `signature` | `string` | The signature that was extracted from the commit. | | `payload` | `string` | The value that was signed. | These are the possible values for `reason` in the `verification` object: | Value | Description | | ----- | ----------- | | `expired_key` | The key that made the signature is expired. | | `not_signing_key` | The "signing" flag is not among the usage flags in the GPG key that made the signature. | | `gpgverify_error` | There was an error communicating with the signature verification service. | | `gpgverify_unavailable` | The signature verification service is currently unavailable. | | `unsigned` | The object does not include a signature. | | `unknown_signature_type` | A non-PGP signature was found in the commit. | | `no_user` | No user was associated with the `committer` email address in the commit. | | `unverified_email` | The `committer` email address in the commit was associated with a user, but the email address is not verified on her/his account. | | `bad_email` | The `committer` email address in the commit is not included in the identities of the PGP key that made the signature. | | `unknown_key` | The key that made the signature has not been registered with any user's account. | | `malformed_signature` | There was an error parsing the signature. | | `invalid` | The signature could not be cryptographically verified using the key whose key-id was found in the signature. | | `valid` | None of the above errors applied, so the signature is considered to be verified. |