ci: publish crates even from HEAD

Modifies the `cargo-release` config to permit releasing from the
`HEAD` checkout created by GHA in CI. By default, cargo-release
disallows `HEAD` via the `!HEAD` match, see docs at [0].

Refs #5005.

[0] https://github.com/crate-ci/cargo-release/blob/f7c2975325afc6d6fc1793544802a5578d9ef256/docs/reference.md

Author: conorsch

Cargo.toml

@@ -106,6 +106,8 @@ push = false
 dependent-version = "upgrade"
 # Increase default ratelimit on publishing packages
 rate-limit = { existing-packages = 50 }
+# Permit publishing from any branch, because in GHA CI context, HEAD is checked out.
+allow-branch = ["*"]
 
 [workspace.package]
 authors    = ["Penumbra Labs <[email protected]"]