add Localstack feature and template repos (#449)

Author: lakkeger

_data/collection-index.yml

@@ -908,3 +908,13 @@
   contact: https://github.com/juan-ayala/devcontainer-templates/issues
   repository: https://github.com/juan-ayala/devcontainer-templates
   ociReference: ghcr.io/juan-ayala/devcontainer-templates
+- name: LocalStack DevContainer Feature
+  maintainer: LocalStack GmbH
+  contact: https://github.com/localstack/devcontainer-feature/issues
+  repository: https://github.com/localstack/devcontainer-feature
+  ociReference: ghcr.io/localstack/devcontainer-feature
+- name: LocalStack DevContainer Template
+  maintainer: LocalStack GmbH
+  contact: https://github.com/localstack/devcontainer-template/issues
+  repository: https://github.com/localstack/devcontainer-template
+  ociReference: ghcr.io/localstack/devcontainer-template