feat: support unauthenticated requests (#59)

GitHub API behaves differently for authenticated and unauthenticated
requests.

For example IP whitelisting for organisations is influenced by the type
of the request.

This will allow unauthenticated requests to GitHub API if `token: ""` is passed.

dist/index.js

@@ -13824,9 +13824,10 @@ var baseFetchAssetFile = async (octokit, { id, outputPath, owner, repo, token })
     repo
   });
   let headers = {
-    accept,
-    authorization: `token ${token}`
+    accept
   };
+  if (token !== "")
+    headers = { ...headers, authorization: `token ${token}` };
   if (typeof userAgent !== "undefined")
     headers = { ...headers, "user-agent": userAgent };
   const response = await fetch(url, { body, headers, method });

index.ts

@@ -88,8 +88,10 @@ const baseFetchAssetFile = async (
   );
   let headers: HeadersInit = {
     accept,
-    authorization: `token ${token}`,
   };
+  if (token !== '')
+    headers = { ...headers, authorization: `token ${token}` };
+
   if (typeof userAgent !== 'undefined')
     headers = { ...headers, 'user-agent': userAgent };