nanvix-zutil v0.12.0

What's Changed

• [zutils] F: Remove NANVIX_VERSION_ env var by @ada-x64 in #255
• [zutils] Remove NANVIX_VERSION env var by @ada-x64 in #256
• [zutils] F: Multi-release by @ada-x64 in #265
• [zutils] E: Backport naming schema by @ada-x64 in #267
• Bump actions/checkout from 6 to 7 by @dependabot[bot] in #262

Full Changelog: v0.11.1...v0.12.0