message: cargo/release: set sign-tag property
  This sets the new `sign-tag` metadata field which has been recently
  by cargo-release.
diff: @@ -60,9 +60,10 @@ failpoints = [ "fail/failpoints" ]
  lto = true
  [package.metadata.release]
  -sign-commit = true
  disable-publish = true
  disable-push = true
  -pre-release-commit-message = "cargo: zincati release {{version}}"
  post-release-commit-message = "cargo: development version bump"
  +pre-release-commit-message = "cargo: zincati release {{version}}"
  +sign-commit = true
  +sign-tag = true
  tag-message = "zincati {{version}}"
  