chore: update dependency ava to v6

Author: renovate[bot]

package.json

@@ -36,7 +36,7 @@
     "@commitlint/travis-cli": "^12.0.0",
     "@untool/eslint-config": "^1.0.0",
     "@untool/prettier-config": "^1.0.0",
-    "ava": "^3.0.0",
+    "ava": "^6.0.0",
     "cz-conventional-changelog": "^3.0.0",
     "eslint": "^7.0.0",
     "esm": "^3.2.25",