Fix path in release-rubygems gem push step for attestation (#179)

Signed-off-by: Samuel Giddins <[email protected]>

Author: segiddins

.github/workflows/release.yml

@@ -151,7 +151,7 @@ jobs:
 
       - name: publish
         run: |
-          gem push "built-packages/$(basename $BUILT_GEM)" --attestation "$(basename $BUILT_GEM).sigstore.json"
+          gem push "built-packages/$(basename $BUILT_GEM)" --attestation "smoketest-artifacts/$(basename $BUILT_GEM).sigstore.json"
         env:
           BUILT_GEM: ${{ matrix.built-gem }}