* Update golang to 1.20
* Fix workflow file to make it work on `1.20`
* Update fieldalignment to 0.24.0
* Remove depricated ioutils
ioutils was depricatd and removed, same API available at `os` and `io`
packages now.
- Replace log.Faltal with error wrapping in schemagen func
- Simplify tests, use temp dir and ioutil functions, remove boilerplate code
- In test use schemagen keyspace to avoid name conflict with examples
- Change template