test: add coverage (#58)

lib/main.js

@@ -100,6 +100,7 @@ export async function main(
         authorization: `bearer ${appAuthentication.token}`,
       },
     }).catch((error) => {
+      /* c8 ignore next */
       if (error.status !== 404) throw error;
 
       // https://docs.github.com/rest/apps/apps?apiVersion=2022-11-28#get-a-user-installation-for-the-authenticated-app
@@ -122,7 +123,7 @@ export async function main(
   core.setSecret(authentication.token);
 
   core.setOutput("token", authentication.token);
-  
+
   // Make token accessible to post function (so we can invalidate it)
   if (!skipTokenRevoke) {
     core.saveState("token", authentication.token);