chore(ci): Add provenance file (#1371)

Add provenance file for releases.

SLSA level 1

Author: JeroenKnoops

.github/workflows/release.yml

@@ -33,6 +33,7 @@ jobs:
           retention-days: 1
 
   release:
+    name: release
     runs-on: ubuntu-latest
     needs:
       prepare
@@ -80,4 +81,21 @@ jobs:
           cp .release/* .
           yarn
           yarn release --repositoryUrl https://x-access-token:[email protected]/$GITHUB_REPOSITORY.git
+          
+  provenance:
+    name: Generate provenance
+    runs-on: ubuntu-20.04
+    needs: 
+      release
+    if: startsWith(github.ref, 'refs/tags/')
+
+    steps:
+      - name: Generate provenance for release
+        uses: philips-labs/[email protected]
+        with:
+          artifact_path: release-assets
+          output_path: 'build.provenance'
+          tag_name: "${{ github.ref_name }}"
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"