Update nette/utils requirement from ^3.0 to ^4.0

Updates the requirements on [nette/utils](https://github.com/nette/utils) to permit the latest version.
- [Release notes](https://github.com/nette/utils/releases)
- [Commits](nette/utils@v3.0.0...v4.0.4)

---
updated-dependencies:
- dependency-name: nette/utils
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

composer.json

@@ -11,7 +11,7 @@
 	"require": {
 		"php": ">=7.1.0",
 		"mpdf/mpdf": "^8.0",
-		"nette/utils": "^3.0",
+		"nette/utils": "^4.0",
 		"latte/latte": "^2.5"
 	},
 	"require-dev": {