Bump anchore/sbom-action from 0.20.11 to 0.21.0 (#2890)

Author: dependabot[bot]

.github/workflows/build.yml

@@ -135,7 +135,7 @@ jobs:
         if-no-files-found: error
 
     - name: Generate SBOM
-      uses: anchore/sbom-action@43a17d6e7add2b5535efe4dcae9952337c479a93 # v0.20.11
+      uses: anchore/sbom-action@a930d0ac434e3182448fe678398ba5713717112a # v0.21.0
       if: runner.os == 'Windows'
       with:
         artifact-name: polly.spdx.json