Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

vendor/thiserror/tests/ui/transparent-struct-source.rs

@@ -0,0 +1,7 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+#[error(transparent)]
+pub struct Error(#[source] anyhow::Error);
+
+fn main() {}