[docs] Change log for v0.12.0 (#1148)
[docs] Change log for v0.12.0 (#1148)

* Change log for v0.12.0

* Add issue #1140

* Remove fixture.before and fixture.after, add test.before and test.after

* Added hammerhead bugs

* Fix links to hammerhead bugs

* Fix Ivan's remarks

* Fix t.ctx example

* Fix typo

* Fix client function example

* customer -> user

georgiy-abbasov/testcafe-phoenix,AndreyBelym/testcafe,AndreyBelym/testcafe,VasilyStrelyaev/testcafe,miherlosev/testcafe,AlexanderMoskovkin/testcafe,churkin/testcafe,churkin/testcafe,inikulin/testcafe,VasilyStrelyaev/testcafe,miherlosev/testcafe,AndreyBelym/testcafe,georgiy-abbasov/testcafe-phoenix,MargaritaLoseva/testcafe,miherlosev/testcafe,DevExpress/testcafe,MargaritaLoseva/testcafe,VasilyStrelyaev/testcafe,VasilyStrelyaev/testcafe,miherlosev/testcafe,AndreyBelym/testcafe,AlexanderMoskovkin/testcafe,MargaritaLoseva/testcafe,AlexanderMoskovkin/testcafe-phoenix,churkin/testcafe,AlexanderMoskovkin/testcafe,churkin/testcafe,georgiy-abbasov/testcafe-phoenix,AndreyBelym/testcafe,VasilyStrelyaev/testcafe,AlexanderMoskovkin/testcafe,MargaritaLoseva/testcafe,DevExpress/testcafe,miherlosev/testcafe,DevExpress/testcafe,DevExpress/testcafe,AlexanderMoskovkin/testcafe-phoenix,inikulin/testcafe,AlexanderMoskovkin/testcafe-phoenix,DevExpress/testcafe