Fix SBOM generation

Author: divolgin

.github/workflows/release.yaml

@@ -29,6 +29,8 @@ jobs:
 
       - name: Install Cosign
         uses: sigstore/cosign-installer@v4.1.2
+        with:
+          cosign-release: 'v3.1.3'
 
       - name: Generate and sign SBOM
         run: make sbom

Makefile

@@ -246,7 +246,8 @@ sbom: sbom/assets/troubleshoot-sbom.tgz
 		--tlog-upload \
 		--yes \
 		--rekor-url=https://rekor.sigstore.dev \
-		sbom/assets/troubleshoot-sbom.tgz > sbom/assets/troubleshoot-sbom.tgz.sig
+		--bundle sbom/assets/troubleshoot-sbom.tgz.bundle \
+		sbom/assets/troubleshoot-sbom.tgz
 	cosign public-key --key cosign.key --outfile sbom/assets/key.pub
 
 .PHONY: get-govulncheck

README.md

@@ -56,19 +56,12 @@ For questions about using Troubleshoot, how to contribute and engaging with the
 # Software Bill of Materials
 A signed SBOM  that includes Troubleshoot dependencies is included in each release.
 - **troubleshoot-sbom.tgz** contains a software bill of materials for Troubleshoot.
-- **troubleshoot-sbom.tgz.sig** is the digital signature for troubleshoot-sbom.tgz
+- **troubleshoot-sbom.tgz.bundle** contains the signature and transparency log material used by Cosign.
 - **key.pub** is the public key from the key pair used to sign troubleshoot-sbom.tgz
 
 The following example illustrates using [cosign](https://github.com/sigstore/cosign) to verify that **troubleshoot-sbom.tgz** has
-not been tampered with.
+not been tampered with. Install [Cosign v3](https://github.com/sigstore/cosign/releases).
 ```sh
-$ cosign verify-blob --key key.pub --signature troubleshoot-sbom.tgz.sig troubleshoot-sbom.tgz
-Verified OK
-```
-
-If you were to get an error similar to the one below, it means you are verifying an SBOM signed using cosign `v1` using a newer `v2` of the binary. This version introduced [breaking changes](https://github.com/sigstore/cosign/blob/main/CHANGELOG.md#breaking-changes) which require an additional flag `--insecure-ignore-tlog=true` to successfully verify SBOMs like so.
-```sh
-$ cosign verify-blob --key key.pub --signature troubleshoot-sbom.tgz.sig troubleshoot-sbom.tgz --insecure-ignore-tlog=true
-WARNING: Skipping tlog verification is an insecure practice that lacks of transparency and auditability verification for the blob.
+$ cosign verify-blob --key key.pub --bundle troubleshoot-sbom.tgz.bundle troubleshoot-sbom.tgz
 Verified OK
 ```