add localdate to account for utc offset in publishing dates

[shahdivyank]

Website change review checklist:

• [x] I have requested a review from the appropriate persons
• [x] I have checked that my changes work in the preview
• [x] I have checked that the rest of the site is still functioning in the preview
• [x] I have checked that my content/code is consistent with existing content/code
• [x] I have used components in the places and ways they are intended (see the readme)
• [x] I have formatted all of my code with Prettier

This pull request:

• Fixes #306
• There was a off by 1 error happening with publishing dates across all lessons due to the UTC vs local timezone formatting
• Now the date posted in the public folder matches the date on the website

[3b1b]

Thank you!