Add my Dev Container Template to index (#533)

* Add my Dev Container Template to index

* resolve merge conflict - collection-index.yml

Author: m-umair-khan-dev

_data/collection-index.yml

@@ -1022,8 +1022,13 @@
   contact: https://github.com/fardragon/devcontainers-zig-template/issues
   repository: https://github.com/fardragon/devcontainers-zig-template
   ociReference: ghcr.io/fardragon/devcontainers-zig-template
+- name: TTCN-3-Devcontainer
+  maintainer: Muhammad Umair Khan
+  contact: https://github.com/m-umair-khan-dev/devcontainers/issues
+  repository: https://github.com/m-umair-khan-dev/devcontainers
+  ociReference: ghcr.io/m-umair-khan-dev/devcontainers/ttcn-3-devcontainer
 - name: Dev Container Features by Grafana Labs
   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