fix: default token only on public github (#157)

* fix: default token only on public github

* docs: document token

Author: xhyrom

action.yml

@@ -41,8 +41,8 @@ inputs:
     description: Disable caching of bun executable.
   token:
     required: false
-    default: ${{ github.token }}
-    description: Personal access token (PAT) used to fetch tags from oven-sh/bun repository. Recommended for resolving wildcard/range versions to avoid GitHub API rate limiting.
+    default: ${{ github.server_url == 'https://github.com' && github.token || '' }}
+    description: Personal access token (PAT) used to fetch tags from oven-sh/bun repository. Recommended for resolving wildcard/range versions to avoid GitHub API rate limiting. When running this action on github.com, the default value is sufficient. When running on GHES, you can pass a personal access token for github.com if you are experiencing rate limiting.
 
 outputs:
   bun-version: