chore(deps): update dependency textlint-tester to v15

Author: renovate[bot]

package-lock.json

@@ -41,7 +41,7 @@
     "prettier": "^3.4.2",
     "textlint-plugin-asciidoctor": "^1.1.0",
     "textlint-scripts": "^14.8.1",
-    "textlint-tester": "^14.8.1",
+    "textlint-tester": "^15.0.0",
     "ts-node": "^10.9.2",
     "typescript": "^5.7.2"
   },