Restore github release provenance + provenance signing

Got accidentally removed https://github.com/philips-labs/slsa-provenance-action/pull/134/files\#diff-944291df2c9c06359d37cc8833d182d705c9e8c3108e7cfe132d61a06e9133ddL197-L212

Signed-off-by: Marco Franssen <marco.franssen@philips.com>

.github/workflows/ci.yaml

@@ -191,6 +191,47 @@ jobs:
           docker logout ghcr.io
           rm -f cosign.key
 
+  provenance:
+    name: provenance
+    needs: [release]
+    if: startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Generate provenance for Release
+        uses: philips-labs/slsa-provenance-action@v0.7.1
+        with:
+          command: generate
+          subcommand: github-release
+          arguments: --artifact-path release-assets --output-path provenance.att --tag-name ${{ github.ref_name }}
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+
+      - name: Install cosign
+        uses: sigstore/cosign-installer@v2.0.0
+        with:
+          cosign-release: 'v1.5.1'
+
+      - name: Sign provenance
+        run: |
+          echo '${{ secrets.COSIGN_PRIVATE_KEY }}' > cosign.key
+          cosign sign-blob --key cosign.key --output-signature "${SIGNATURE}" provenance.att
+          cat "${SIGNATURE}"
+
+          curl_args=(-s -H "Authorization: token ${GITHUB_TOKEN}")
+          curl_args+=(-H "Accept: application/vnd.github.v3+json")
+          release_id="$(curl "${curl_args[@]}" "${GITHUB_API_URL}/repos/${GITHUB_REPOSITORY}/releases?per_page=10" | jq "map(select(.name == \"${GITHUB_REF_NAME}\"))" | jq -r '.[0].id')"
+
+          echo "Upload ${SIGNATURE} to release with id ${release_id}…"
+          curl_args+=(-H "Content-Type: $(file -b --mime-type "${SIGNATURE}")")
+          curl "${curl_args[@]}" \
+            --data-binary @"${SIGNATURE}" \
+            "https://uploads.github.com/repos/${GITHUB_REPOSITORY}/releases/${release_id}/assets?name=${SIGNATURE}"
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+          COSIGN_PASSWORD: ${{ secrets.COSIGN_PASSWORD }}
+          SIGNATURE: provenance.att.sig
+
   container-provenance:
     name: container-provenance
     needs: [release]
@@ -208,7 +249,7 @@ jobs:
           cosign-release: 'v1.5.1'
 
       - name: Generate provenance for ${{ matrix.repo }}
-        uses: philips-labs/slsa-provenance-action@v0.8.1-draft
+        uses: philips-labs/slsa-provenance-action@v0.7.1
         with:
           command: generate
           subcommand: container