chore(deps): update dependency is-ci to v4 (#704)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -46,7 +46,7 @@
     "eslint-plugin-astro": "0.34.0",
     "eslint-plugin-prettier": "5.4.0",
     "husky": "9.1.7",
-    "is-ci": "3.0.1",
+    "is-ci": "4.1.0",
     "lint-staged": "15.5.2",
     "prettier": "3.5.3",
     "prettier-plugin-astro": "0.14.1",