Update .github/ISSUE_TEMPLATE/converter_request.md

Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

Author: C4illin

.github/ISSUE_TEMPLATE/converter_request.md

@@ -6,7 +6,7 @@ labels: "converter request"
 assignees: ""
 ---
 
-**What file formats is missing?**
+**What file formats are missing?**
 
 <!-- Provide an example of what you would like to convert -->