update setup

• build: remove composer.lock from template
• build: add WP Desk as package author
• build: declare latest low support version
• build: remove composer's platform check
• build: add phpstan as direct dependency/update phpunit
• refactor: update phpunit setup and example test
• build: update phpstan config

composer.json

@@ -33,7 +33,8 @@
 			"wpdesk/wp-codeception": true,
 			"wpdesk/wp-wpdesk-composer": true,
 			"kylekatarnls/update-helper": true
-		}
+		},
+		"platform-check": false
 	},
 	"prefer-stable": true,
 	"minimum-stability": "stable",