ci: fix uploading build artifacts to S3 for freebsd

When the `freebsd` workflow has become a matrix one in 0bd15468
("ci: mv freebsd testing from per-commit to nightly"), we forgot
to do the corresponding changes in the `Upload artifacts to S3` step.
So adding missing changes.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

(cherry picked from commit 5fa3d5a2)

.github/workflows/freebsd.yml

@@ -70,7 +70,7 @@ jobs:
           startsWith(github.ref, 'refs/heads/release/') ||
           startsWith(github.ref, 'refs/tags/') )
         with:
-          job-name: ${{ github.job }}
+          job-name: ${{ github.job }} (${{ join(matrix.*, ', ') }})
           access-key-id: ${{ secrets.MULTIVAC_S3_ACCESS_KEY_ID }}
           secret-access-key: ${{ secrets.MULTIVAC_S3_SECRET_ACCESS_KEY }}
           source: ${{ env.VARDIR }}/artifacts