chore(.env.example): add comment for GH token key usage

Author: TylerAPfledderer

.env.example

@@ -7,6 +7,8 @@
 # NEXT_PUBLIC_ALGOLIA_APP_ID=insertValue
 # NEXT_PUBLIC_ALGOLIA_SEARCH_KEY=insertValue
 # NEXT_PUBLIC_ALGOLIA_BASE_SEARCH_INDEX_NAME=insertValue
+
+# Github token for read-only use with api functions
 # NEXT_PUBLIC_GITHUB_TOKEN_READ_ONLY=insertValue
 
 # Etherscan API key (required for Etherscan API fetches)