ErrorKind::Unsupported is rust 1.53 and up

This isn't a hard requirement, but tracking 1.53 doesn't
feel like a burden as 1.54 is now the stable rust version.

get-deps

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-min_rust=(1 51 0)
+min_rust=(1 53 0)
 rust_ver=()
 
 parse_rustc_version() {