[ecm] update to 6.29.0

[toge (toge)]

• Changes comply with the maintainer guide.
• SHA512s are updated for each updated download.
• The "supports" clause reflects platforms that may be fixed by this new version, or no changes were necessary.
• Any fixed CI baseline and CI feature baseline entries are removed from that file, or no entries needed to be changed.
• All patch files in the port are applied and succeed.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Exactly one version is added in each modified versions file.

https://invent.kde.org/frameworks/extra-cmake-modules/-/tags/v6.29.0

[Billy O'Neal (BillyONeal)]

GPT 5.6 Sol reports:

• The current ports/ecm/vcpkg.json and proposed ports/ecm/vcpkg.json omit the installed content's licenses. The package includes BSD-3-Clause, BSD-2-Clause, CC0-1.0, GPL-2.0-or-later, and MIT content, while ports/ecm/portfile.cmake installs only the BSD-style COPYING-CMAKE-SCRIPTS. This should be reconciled with the vcpkg maintainer guide's copyright and licensing requirements.
• ports/ecm/usage uses CRLF line endings

Would you consider toge#53 ?