Upgrade several dependencies (#84)

* These upgrades did not change the operation of the scripts `mkdocs` or
 `test`.
* Remove `rimraf`, which appears to be unused.

Author: spl

package.json

@@ -28,18 +28,17 @@
     "@babel/register": "^7.13.8",
     "babel-loader": "^8.0.6",
     "chai": "^4.3.4",
-    "coveralls": "^3.0.9",
+    "coveralls": "^3.1.1",
     "docsify-cli": "^4.4.3",
     "eslint": "7.9.0",
     "eslint-config-prettier": "6.11.0",
     "eslint-plugin-prettier": "3.1.3",
     "html-webpack-plugin": "^5.3.1",
-    "jsdoc-to-markdown": "^7.0.1",
-    "mocha": "^8.3.2",
-    "nyc": "^15.0.0",
+    "jsdoc-to-markdown": "^7.1.0",
+    "mocha": "^9.1.3",
+    "nyc": "^15.1.0",
     "prettier": "^1.19.1",
-    "rimraf": "^2.7.1",
-    "sinon": "^9.2.4",
+    "sinon": "^12.0.1",
     "typescript": "^4.2.3",
     "webpack": "^5.36.2",
     "webpack-cli": "^4.6.0",