Go version support?

[capnspacehook]

I am working on a patch that would really benefit from errors.Is, but I am unsure whether I can use it or not. The go.mod file is at Go version 1.13, but you still support Go 1.12 and earlier. Is that a mistake or intentional, and would you be willing to drop support for Go 1.12 and earlier for better handling of errors? If so I could send a PR.

[florianl]

With commit 3cf809d I have updated the minimal required Go version to 1.14 and subsequently removed legacy code.
Once PR #17 is merged, I plan to tag a new version.

Hope this resolves concerns :)

[capnspacehook]

Awesome, yes that's perfect!