test: replace chai with Node.js assert to reduce dependency (#64)

* chore: replace `chai` with Node.js assert to reduce dependency footprint

* wip: remove `node:` namespace

Author: lumirlumir

package.json

@@ -39,7 +39,6 @@
   },
   "homepage": "https://github.com/eslint/eslint-release#readme",
   "devDependencies": {
-    "chai": "^4.2.0",
     "eslint": "^7.25.0",
     "eslint-config-eslint": "^7.0.0",
     "eslint-plugin-jsdoc": "^32.3.1",

tests/lib/release-ops.js

@@ -11,7 +11,7 @@
 // Requirements
 //------------------------------------------------------------------------------
 
-const assert = require("chai").assert,
+const assert = require("assert"),
     fs = require("fs"),
     leche = require("leche"),
     os = require("os"),

tests/lib/shell-ops.js

@@ -11,7 +11,7 @@
 // Requirements
 //------------------------------------------------------------------------------
 
-const assert = require("chai").assert,
+const assert = require("assert"),
     sinon = require("sinon"),
     path = require("path"),
     leche = require("leche"),