Fix assetresolver error with age-keygen install

Similar to #50, this fixes assetresolver errors during the age-keygen install from proof files matching incorrectly.

Author: mattkaar

src/age-keygen/install.sh

@@ -13,6 +13,6 @@ $nanolayer_location \
     install \
     devcontainer-feature \
     "ghcr.io/devcontainers-extra/features/gh-release:1.0.26" \
-    --option repo='filosottile/age' --option binaryNames='age-keygen' --option version="$VERSION"
+    --option repo='filosottile/age' --option binaryNames='age-keygen' --option version="$VERSION" --option assetRegex='.*(.tar.gz)$'
 
 echo 'Done!'