Update anchore/sbom-action action to v0.20.6 (#1133)

| datasource  | package             | from    | to      |
| ----------- | ------------------- | ------- | ------- |
| github-tags | anchore/sbom-action | v0.20.5 | v0.20.6 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -155,7 +155,7 @@ jobs:
         if: github.event_name != 'pull_request'
 
       - name: Download Syft
-        uses: anchore/sbom-action/download-syft@da167eac915b4e86f08b264dbdbc867b61be6f0c # v0.20.5
+        uses: anchore/sbom-action/download-syft@f8bdd1d8ac5e901a77a92f111440fdb1b593736b # v0.20.6
         if: github.ref_type == 'tag'
 
       - name: Install Cosign