Add NicoVIII devcontainer-features to collection-index (#681)

* Update collection-index.yml

* Update collection-index.yml

Change ociReference to be lowercase

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Co-authored-by: Abdurrahmaan Iqbal <abdurriq@github.com>

Author: NicoVIII

_data/collection-index.yml

@@ -1461,3 +1461,8 @@
   contact: https://github.com/postfinance/devcontainer-features/issues
   repository: https://github.com/postfinance/devcontainer-features
   ociReference: ghcr.io/postfinance/devcontainer-features
+- name: Devcontainer Features by NicoVIII
+  maintainer: NicoVIII
+  contact: https://github.com/NicoVIII/devcontainer-features/issues
+  repository: https://github.com/NicoVIII/devcontainer-features
+  ociReference: ghcr.io/nicoviii/devcontainer-features