Release 2.0.26 (#4087)

- setting "rounding days" not required
- developer: added user pref for public holiday group (to be used by plugins)
- developer: added WorkingTimeYearEvent (to be used by plugins)
- user pref: cleanup work contract form and support more fields (to be used by plugins)
- code cleanup
- bump theme and composer packages

tests/phpstan.neon

@@ -6582,11 +6582,6 @@ parameters:
             count: 1
             path: Form/Type/TypeTestModel.php
 
-        -
-            message: "#^Method App\\\\Tests\\\\Form\\\\Type\\\\TypeTestModel\\:\\:__set\\(\\) has no return type specified\\.$#"
-            count: 1
-            path: Form/Type/TypeTestModel.php
-
         -
             message: "#^Method App\\\\Tests\\\\Form\\\\Type\\\\TypeTestModel\\:\\:__set\\(\\) has parameter \\$name with no type specified\\.$#"
             count: 1