bootc 1.16.4

Features

Improved handling of merging files in /etc
- Etc merge changes by @Johan-Liebert1 in #2301

initramfs: tolerate pre-existing /run/systemd/volatile-root symlink by @ricardosalveti in #2276
Composefs changes, disable failing ostree test by @Johan-Liebert1 in #2277
UKI Cleanup by @Johan-Liebert1 in #2200
Sync common files from infra repository by @bootc-bot[bot] in #2282
ci: Don't let heavy jobs block merge-queue entry in PRs by @cgwalters in #2274
Replace local bootc-kernel-cmdline crate with linux-kernel-cmdline by @jeckersb in #2297
Update composefs-rs by @cgwalters in #2295
ci: A few improvements by @cgwalters in #2293
docs/composefs: Update with latest by @cgwalters in #2298
composefs/bls: Add user provided kargs by @Johan-Liebert1 in #2305
ostree-ext: Remove privilege dropping for container pulls by @gursewak1997 in #2307
ostree-ext: Remove unused isolation parameter and proxy indirection by @gursewak1997 in #2312
Update Rust by @bootc-bot[bot] in #2308
ci: Run unit tests once per OS instead of once per test-integration leg by @cgwalters in #2311
Release 1.16.4 by @bootc-bot[bot] in #2310

Full Changelog: v1.16.3...v1.16.4