add header checker

config.yaml

@@ -11,6 +11,10 @@ upstream:
   path:
     match: /(debian|ubuntu|ubuntu-releases|alpine|archlinux|kali|manjaro|msys2|almalinux|rocky|centos|centos-stream|centos-vault|fedora|epel|elrepo|remi|rpmfusion|tailscale|gnu|rust-static|pypi)/(.*)
     replace: '/$1/$2'
+  checkers:
+    headers:
+    - name: content-type
+      match: application/octet-stream
 - server: https://packages.microsoft.com/repos/code
   path:
     match: /microsoft-code(.*)