CI: dont generate index since no signing key

Signed-off-by: Tianling Shen <[email protected]>

.github/workflows/multi-arch-test-build.yml

@@ -73,7 +73,6 @@ jobs:
         env:
           ARCH: ${{ matrix.arch }}
           FEEDNAME: packages_ci
-          INDEX: 1
           V: s
 
       - name: Move created packages to project dir