Bump proc-macro2 from 1.0.5 to 1.0.6 (#223)
Bump proc-macro2 from 1.0.5 to 1.0.6 (#223)

Bumps [proc-macro2](https://github.com/alexcrichton/proc-macro2) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/alexcrichton/proc-macro2/releases)
- [Commits](https://github.com/alexcrichton/proc-macro2/compare/1.0.5...1.0.6)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
alex/csv-sql