Re-add license notes

Author: jrdnbradford

src/check_jsonschema/builtin_schemas/vendor/README.md

@@ -8,3 +8,29 @@ For the exact list of schemas here, see the repo root for hook config.
 Most of the schemas in this directory are provided by SchemaStore. They are
 therefore licensed under the SchemaStore license, included in this directory.
 Additional licenses can be found in [`licenses`](licenses).
+
+### Azure Pipelines
+
+The Azure pipelines schema is provided by Microsoft and is licensed under the
+license for azure-pipelines-vscode.
+
+### ReadTheDocs
+
+The ReadTheDocs schema is provided by ReadTheDocs and licensed under the
+license for readthedocs.org
+
+### Renovate
+
+The Renovate schema is provided by Renovate and licensed under the license for
+renovatebot
+
+### GitLab
+
+The GitLab CI schema is provided by GitLab and licensed under the license for
+the public gitlab repo. In particular, it falls under the "MIT Expat" portion
+of the license for that repo.
+
+### Buildkite
+
+The Buildkite schema is provided by Buildkite and licensed under the license
+for their 'pipeline-schema' repo.