Update dompdf/dompdf requirement from ^2.0 to ^2.0 || ^3.0

Updates the requirements on [dompdf/dompdf](https://github.com/dompdf/dompdf) to permit the latest version.
- [Release notes](https://github.com/dompdf/dompdf/releases)
- [Commits](dompdf/dompdf@v2.0.0...v3.0.0)

---
updated-dependencies:
- dependency-name: dompdf/dompdf
  dependency-type: direct:development
...

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

composer.json

@@ -68,7 +68,7 @@
         "ext-zip": "*",
         "ext-gd": "*",
         "ext-libxml": "*",
-        "dompdf/dompdf": "^2.0",
+        "dompdf/dompdf": "^2.0 || ^3.0",
         "mpdf/mpdf": "^8.1",
         "php-coveralls/php-coveralls": "^2.5",
         "phpmd/phpmd": "^2.13",