amplify_syn 1.1.5

Amplifying syn capabilities: helper functions for creating proc macro libraries
Change Log

- Custom parsers allowing attribute values to take any form, not only literals
- Convenience methods for ArgValue conversion from/to idents & paths
- `ident!` macros for simplified `syn::Ident` creation

- Fixing sample code URL in README
- Renaming `ArgReq` to `ArgValReq` (since the old name)
- Yanking 1.0.0 version (since the rename is breaking backward compatibility)