correct manifest and artifacts dir

.gitignore

@@ -22,4 +22,4 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 
-artifacts
+build/artifacts

public/manifest.json

@@ -9,6 +9,11 @@
   },
   "browser_action": {
     "default_icon": "logo192.png",
+    "theme_icons": [{
+        "light": "logo192.png",
+        "dark": "logo192.png",
+        "size": 192
+    }],
     "default_title": "TimeConvert",
     "default_popup": "index.html",
     "browser_style": true

webext.config.js

@@ -1,6 +1,6 @@
 module.exports = {
    sourceDir: "./build",
-   artifactsDir: "./artifacts",
+   artifactsDir: "./build/artifacts",
    build: {
       overwriteDest: true
    }