Add sebdanielsson's template collection

Author: sebdanielsson

_data/collection-index.yml

@@ -1036,4 +1036,9 @@
   maintainer: Grafana Labs
   contact: https://github.com/grafana/devcontainer-features/issues
   repository: https://github.com/grafana/devcontainer-features
-  ociReference: ghcr.io/grafana/devcontainer-features
+  ociReference: ghcr.io/grafana/devcontainer-features
+- name: sebdanielsson's templates
+  maintainer: Sebastian Danielsson (@sebdanielsson)
+  contact: https://github.com/sebdanielsson/devcontainers/issues
+  repository: https://github.com/sebdanielsson/devcontainers
+  ociReference: http://ghcr.io/sebdanielsson/devcontainers