Update Linear Integration extension to v0.5.0 (#2995)

Update linear extension submitted by @ashbrener:
- extensions/catalog.community.json (version, download_url, updated_at)

Closes #2953

Co-authored-by: Manfred Riem <mnriem@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mnriem

extensions/catalog.community.json

@@ -1465,8 +1465,8 @@
       "id": "linear",
       "description": "Mirror spec-kit feature directories into Linear (filesystem → Linear, reconcile-based, unidirectional).",
       "author": "Ash Brener",
-      "version": "0.4.0",
-      "download_url": "https://github.com/ashbrener/spec-kit-linear-sync/archive/refs/tags/v0.4.0.zip",
+      "version": "0.5.0",
+      "download_url": "https://github.com/ashbrener/spec-kit-linear-sync/archive/refs/tags/v0.5.0.zip",
       "repository": "https://github.com/ashbrener/spec-kit-linear-sync",
       "homepage": "https://github.com/ashbrener/spec-kit-linear-sync",
       "documentation": "https://github.com/ashbrener/spec-kit-linear-sync/blob/main/README.md",
@@ -1493,7 +1493,7 @@
       "downloads": 0,
       "stars": 0,
       "created_at": "2026-06-01T00:00:00Z",
-      "updated_at": "2026-06-11T00:00:00Z"
+      "updated_at": "2026-06-16T00:00:00Z"
     },
     "m365": {
       "name": "Microsoft 365 Integration",