Remove unnecessary SQLite file creation in test workflow

[maru0914]

In the test workflow (tests.yml), SQLite file creation is included.
However, since phpunit.xml configures SQLite to run in memory during test execution, SQLite file is not needed in the test CI.

livewire-starter-kit/phpunit.xml

Lines 25 to 26 in a2d6925

	<env name="DB_CONNECTION" value="sqlite"/>
	<env name="DB_DATABASE" value=":memory:"/>

I’ve also submitted same PRs for the Vue and React starter kits:
Vue: laravel/vue-starter-kit#56
React: laravel/react-starter-kit#52

[tnylea]

Looks great!