[sigstore-conformance]enable delete branch on merge for all current repos in sigstore-conformance

[cpanato]

Summary

• enable delete branch on merge for all current repos in sigstore-conformance

also to test the changes added in #293

[github-actions]

🍹 preview on sigstore-github-sync/sigstore/github-sigstore-conformance

Pulumi report

Previewing update (sigstore/github-sigstore-conformance)

View Live: https://app.pulumi.com/sigstore/sigstore-github-sync/github-sigstore-conformance/previews/36f92be9-21a5-4d2b-aa97-cca17985a281

@ Previewing update.....
pulumi:pulumi:Stack: (same)
[urn=urn:pulumi:github-sigstore-conformance::sigstore-github-sync::pulumi:pulumi:Stack::sigstore-github-sync-github-sigstore-conformance]
~ github:index/repository:Repository: (update) 🔒
    [id=extremely-dangerous-public-oidc-beacon]
    [urn=urn:pulumi:github-sigstore-conformance::sigstore-github-sync::github:index/repository:Repository::extremely-dangerous-public-oidc-beacon]
  ~ deleteBranchOnMerge: false => true
~ github:index/repository:Repository: (update) 🔒
    [id=.github]
    [urn=urn:pulumi:github-sigstore-conformance::sigstore-github-sync::github:index/repository:Repository::.github]
  ~ deleteBranchOnMerge: false => true
Resources:
~ 2 to update
13 unchanged

[cpanato]

need #297