devel/qtcreator: Update to 13.0.0 release.

Additional changes by jhale:

• Add LIBSECRET option to handle libsecret support in the bundled qtkeychain library
• Fix pkg-plist when WITH_DEBUG is set
• Set environment when building docs to eliminate warnings about a UTF-8 LOCALE not being set

Changes: https://www.qt.io/blog/qt-creator-13-released

PR: 278200
(cherry picked from commit 9e251d0efb9fab2729c2e777ce14fb96b13d6f35)