chore(starters): Remove unnecessary main keys from package.json (#34942)

Author: tyhopp

starters/blog/package.json

@@ -40,7 +40,6 @@
     "gatsby"
   ],
   "license": "0BSD",
-  "main": "n/a",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/gatsbyjs/gatsby-starter-blog.git"

starters/gatsby-starter-theme-workspace/example/package.json

@@ -1,7 +1,6 @@
 {
   "name": "example",
   "version": "1.0.0",
-  "main": "index.js",
   "author": "christopherbiscardi <[email protected]> (@chrisbiscardi)",
   "license": "MIT",
   "scripts": {

starters/gatsby-starter-theme-workspace/package.json

@@ -2,7 +2,6 @@
   "name": "gatsby-starter-theme-workspace",
   "private": true,
   "version": "0.0.1",
-  "main": "index.js",
   "license": "0BSD",
   "scripts": {
     "build": "yarn workspace example build"

starters/gatsby-starter-wordpress-blog/package.json

@@ -34,7 +34,6 @@
     "gatsby"
   ],
   "license": "0BSD",
-  "main": "n/a",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/gatsbyjs/gatsby-starter-blog.git"