Fixes from phpstan checks, add PHP CI/CD github action

src/Logging/Logger/Level.php

@@ -86,7 +86,7 @@ enum Level: int
 
 	/**
 	 * @param value-of<self::NAMES>|LogLevel::*|'Debug'|'Info'|'Notice'|'Warning'|'Error'|'Critical'|'Alert'|'Emergency' $name
-	 * @return static
+	 * @return self
 	 */
 	public static function fromName(string $name): self
 	{
@@ -104,7 +104,7 @@ enum Level: int
 
 	/**
 	 * @param value-of<self::VALUES> $value
-	 * @return static
+	 * @return self
 	 */
 	public static function fromValue(int $value): self
 	{