Use latest versions of development dependencies

We thought we already did this in e24b501, but instead we would
basically get random versions as npm would pick some version already
available from whatever was already downloaded.

New attempt, this time being very explicit that we want the version that
has been tagged as "latest".

package.json

@@ -38,36 +38,36 @@
   },
   "homepage": "https://github.com/novnc/noVNC",
   "devDependencies": {
-    "@babel/core": "*",
-    "@babel/plugin-syntax-dynamic-import": "*",
-    "@babel/plugin-transform-modules-commonjs": "*",
-    "@babel/preset-env": "*",
-    "@babel/cli": "*",
-    "babel-plugin-import-redirect": "*",
-    "browserify": "*",
-    "babelify": "*",
-    "core-js": "*",
-    "chai": "*",
-    "commander": "*",
-    "es-module-loader": "*",
-    "eslint": "*",
-    "fs-extra": "*",
-    "jsdom": "*",
-    "karma": "*",
-    "karma-mocha": "*",
-    "karma-chrome-launcher": "*",
-    "@chiragrupani/karma-chromium-edge-launcher": "*",
-    "karma-firefox-launcher": "*",
-    "karma-ie-launcher": "*",
-    "karma-mocha-reporter": "*",
-    "karma-safari-launcher": "*",
-    "karma-script-launcher": "*",
-    "karma-sinon-chai": "*",
-    "mocha": "*",
-    "node-getopt": "*",
-    "po2json": "*",
-    "sinon": "*",
-    "sinon-chai": "*"
+    "@babel/core": "latest",
+    "@babel/plugin-syntax-dynamic-import": "latest",
+    "@babel/plugin-transform-modules-commonjs": "latest",
+    "@babel/preset-env": "latest",
+    "@babel/cli": "latest",
+    "babel-plugin-import-redirect": "latest",
+    "browserify": "latest",
+    "babelify": "latest",
+    "core-js": "latest",
+    "chai": "latest",
+    "commander": "latest",
+    "es-module-loader": "latest",
+    "eslint": "latest",
+    "fs-extra": "latest",
+    "jsdom": "latest",
+    "karma": "latest",
+    "karma-mocha": "latest",
+    "karma-chrome-launcher": "latest",
+    "@chiragrupani/karma-chromium-edge-launcher": "latest",
+    "karma-firefox-launcher": "latest",
+    "karma-ie-launcher": "latest",
+    "karma-mocha-reporter": "latest",
+    "karma-safari-launcher": "latest",
+    "karma-script-launcher": "latest",
+    "karma-sinon-chai": "latest",
+    "mocha": "latest",
+    "node-getopt": "latest",
+    "po2json": "latest",
+    "sinon": "latest",
+    "sinon-chai": "latest"
   },
   "dependencies": {},
   "keywords": [