docs: add opencode-skills-collection to plugins

data/plugins/opencode-skills-collection.yaml

@@ -0,0 +1,9 @@
+name: opencode-skills-collection
+repo: https://github.com/FrancoStino/opencode-skills-collection
+npm: opencode-skills-collection
+tagline: OpenCode CLI plugin that automatically downloads and keeps skills up to date.
+description: OpenCode Skills Collection is a OpenCode plugin that automatically downloads and keeps Skills up to date
+kind: plugin
+topics:
+  - prompting
+compat: v2