update promo tiles, add tutorial for publishing new versions

Author: zubyj

build/PUBLISHING.md

@@ -1,21 +1,24 @@
-Here are the steps to publishing the extension
+# Publishing the extension
 
-Run this command 
+1. Make sure the version number is updated in manifest.json
 
-`
+2. Remove dev files not used in production
+```
 rm -r .git .gitignore docs build src/background src/content-script src/popup.ts src/settings.ts images/
-`
+```
 
-The only files that should be published are
+The only files that remain should be
 
-1. dist folder
-2. node modules 
-3. HTML/CSS/JS files in src
+1. dist folder (Compiled TS files)
+2. node modules (only the referenced node modules in GPT folder)
+3. HTML/CSS/JS files in src directory
 4. Icons for logos and buttons
 
 Everything else should be removed
 - Hidden Git files (.git and .gitignore)
 - All typescript files 
 - Screenshots from images folder
-- package, tsconfig, webpack files?
+- package, tsconfig, webpack files
+
+Then zip the file into leetcode-explained.zip and submit. I like to use [Keka](https://www.keka.io/en/).