Bump @antora/atlas-extension in /antora

---
updated-dependencies:
- dependency-name: "@antora/atlas-extension"
  dependency-version: 1.0.0-alpha.5
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

See gh-47211

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

antora/package-lock.json

@@ -6,7 +6,7 @@
   "dependencies": {
     "@antora/cli": "3.2.0-alpha.10",
     "@antora/site-generator": "3.2.0-alpha.4",
-    "@antora/atlas-extension": "1.0.0-alpha.2",
+    "@antora/atlas-extension": "1.0.0-alpha.5",
     "@springio/antora-extensions": "1.14.7",
     "@springio/antora-xref-extension": "1.0.0-alpha.4",
     "@springio/antora-zip-contents-collector-extension": "1.0.0-alpha.8",