Handle missing issues

Author: matejchalk

__tests__/__snapshots__/main.test.ts.snap

@@ -14,6 +14,7 @@ exports[`code-pushup action pull request event should compare reports 1`] = `
 |:--|:--|:--:|:--:|:--:|
 |TypeScript migration|Source files converted from JavaScript to TypeScript|🟩 **100% converted**|🟨 50% converted|![↑ +100 %](https://img.shields.io/badge/%E2%86%91%20%2B100%E2%80%89%25-green)|
 
+
 </details>
 "
 `;

dist/index.js

@@ -70,7 +70,7 @@ function getAuditIssues(
 ): SourceFileIssue[] {
   return (
     audit.details?.issues
-      .filter((issue): issue is Required<Issue> => issue.source?.file != null)
+      ?.filter((issue): issue is Required<Issue> => issue.source?.file != null)
       .map(issue => ({ ...issue, audit, plugin })) ?? []
   )
 }