repo: correct typo

Author: compnerd

default.xml

@@ -28,7 +28,7 @@
   <project remote="github" name="apple/swift-llbuild" path="llbuild" />
   <project remote="github" name="apple/swift-lmdb" path="swift-lmdb" />
   <project remote="github" name="apple/swift-log" path="swift-log" groups="notdefault" />
-  <project remote="github" name="apple/siwft-markdown" path="swift-markdown" />
+  <project remote="github" name="apple/swift-markdown" path="swift-markdown" />
   <project remote="github" name="apple/swift-nio" path="swift-nio" groups="notdefault" />
   <project remote="github" name="apple/swift-numerics" path="swift-numerics" groups="notdefault" />
   <project remote="github" name="apple/swift-package-manager" path="swift-package-manager" />