Upgrade to antora-zip-contents-collector-extension 1.0.0-alpha.8

Closes gh-40598

Author: philwebb

antora/package-lock.json

@@ -8,7 +8,7 @@
     "@antora/atlas-extension": "1.0.0-alpha.2",
     "@springio/antora-extensions": "1.8.2",
     "@springio/antora-xref-extension": "1.0.0-alpha.3",
-    "@springio/antora-zip-contents-collector-extension": "1.0.0-alpha.7",
+    "@springio/antora-zip-contents-collector-extension": "1.0.0-alpha.8",
     "@asciidoctor/tabs": "1.0.0-beta.6",
     "@springio/asciidoctor-extensions": "1.0.0-alpha.10"
   },