Paths should be relative to the "sceptre directory" specified in if the "--dir" flag if it is used

[mike-rsi]

You can specify the --dir flag when running sceptre from anywhere other than the root of your project. When you do so, any relative paths used with the !file resolver break because the !file resolver looks for files relative to the directory you run sceptre from, not relative to the directory provided by the --dir flag. If --dir is specified, !file should try and load files relative to the path specified there. This will make the Sceptre config files more portable.