workflows: do not error on upload step if there are no debs

As is the case when using ci:no-build for example.

.github/workflows/packages.yml

@@ -164,7 +164,12 @@ jobs:
         # This makes it easier to parse it, we can run one update job
         # instead of one for each arch on the server.
         archive="termux-packages-${{ github.sha }}.zip"
-        zip $archive debs-*-${{ github.sha }}.tar
-        sftp -P ${{ secrets.PORT }} ${{ secrets.USER }}@grimler.se <<EOF
-          put $archive /debs/
-        EOF
+        deb_archives=$(find -maxdepth -name "debs-*-${{ github.sha }}.tar")
+        if [ -n "$deb_archives" ]; then
+          zip $archive ${deb_archives}
+          sftp -P ${{ secrets.PORT }} ${{ secrets.USER }}@grimler.se <<EOF
+            put $archive /debs/
+          EOF
+        else
+          echo "No archives to upload found"
+        fi