chore(main): release 6.0.0

[nodejs-github-bot]

:robot: I have created a release beep boop

6.0.0 (2025-12-16)

⚠ BREAKING CHANGES

• drop Node.js 18.x from supported engines (#988)

Features

• git-node: enhance remote configuration error message (#965) (ea17768)
• git-node: verify tag with official keyring (#989) (48a418b)
• ncu-config: add support for partially encrypted config files (#1004) (7342aff)

Bug Fixes

• git-node: clarify remote configuration error message (#1001) (8746db3)
• git-node: harmonize time left error messages (#1007) (d5a488f)
• git-node: include full URL in suggested gh command (#1002) (caee3c5)
• ncu-config: do not override encrypted values silently (#1006) (5d72b3e)
• remove stack traces from non-debug output (#990) (687217f)
• spawning of gpg to read config (#991) (100c694)

Miscellaneous Chores

• drop Node.js 18.x from supported engines (#988) (f8371dd)

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