fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-INFLIGHT-6095116

package.json

@@ -78,9 +78,9 @@
     "cross-env": "^7.0.3",
     "execa": "^5.0.0",
     "gaxios": "^4.0.0",
-    "gts": "^2.0.0",
+    "gts": "^3.0.0",
     "js-green-licenses": "^3.0.0",
-    "linkinator": "^2.0.0",
+    "linkinator": "^4.1.3",
     "mkdirp": "^1.0.0",
     "mocha": "^8.1.3",
     "mv": "^2.1.1",
@@ -91,7 +91,7 @@
     "p-queue": "^6.0.0",
     "prettier": "^2.0.5",
     "proxyquire": "^2.1.3",
-    "rimraf": "^3.0.2",
+    "rimraf": "^4.0.0",
     "server-destroy": "^1.0.1",
     "sinon": "^11.0.0",
     "tmp": "^0.2.0",