Add script to update translations

Signed-off-by: Lukas Holecek <hluk@email.cz>

docs/translations.rst

@@ -38,7 +38,7 @@ To add new language for the application follow these steps.
 
 1. Edit ``copyq.pro`` and add file name for new language
    (``translations/copyq_<LANGUAGE>.ts``) to ``TRANSLATIONS`` variable.
-2. Create new language file with ``lupdate copyq.pro``.
+2. Create new language file with ``utils/lupdate.sh``.
 3. Add new language file to Git repository.
 4. Translate with Weblate service or locally with
    ``linguist translations/copyq_<LANGUAGE>.ts``.

utils/lupdate.sh

+#!/bin/bash
+exec "${LUPDATE:-lupdate-qt5}" src/ plugins/*/*.{cpp,h,ui} -ts translations/*.ts