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

@@ -3,7 +3,12 @@
 	"authors": [
 		{
 			"name": "Krzysiek",
-			"email": "krzysiek@wpdesk.net"
+			"email": "krzysiek@wpdesk.net",
+			"role": "Lead Developer"
+		},
+		{
+			"name": "WP Desk",
+			"role": "Owner"
 		}
 	],
 	"autoload": {