chore(deps): update anchore/sbom-action action to v0.20.6 (#267)

| 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

@@ -64,7 +64,7 @@ jobs:
       run: dotnet test --configuration Release --logger:"GitHubActions;report-warnings=false"
 
     - name: Generate SBOM
-      uses: anchore/sbom-action@da167eac915b4e86f08b264dbdbc867b61be6f0c # v0.20.5
+      uses: anchore/sbom-action@f8bdd1d8ac5e901a77a92f111440fdb1b593736b # v0.20.6
       if: runner.os == 'Windows'
       with:
         artifact-name: grafana-opentelemetry-dotnet.spdx.json