chore(deps): update anchore/sbom-action action to v0.20.8 (#308)

| datasource  | package             | from    | to      |
| ----------- | ------------------- | ------- | ------- |
| github-tags | anchore/sbom-action | v0.20.7 | v0.20.8 |

Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>
Co-authored-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

.github/workflows/ci.yml

@@ -65,7 +65,7 @@ jobs:
       run: dotnet test --configuration Release --logger:"GitHubActions;report-warnings=false"
 
     - name: Generate SBOM
-      uses: anchore/sbom-action@d8a2c0130026bf585de5c176ab8f7ce62d75bf04 # v0.20.7
+      uses: anchore/sbom-action@aa0e114b2e19480f157109b9922bda359bd98b90 # v0.20.8
       if: runner.os == 'Windows'
       with:
         artifact-name: grafana-opentelemetry-dotnet.spdx.json