* Bump CI to Go 1.19
* Update golang/go edwards25519 test
* Apply formatting to printer stubs output (to get correct comment formatting)
* Bump gofumpt version
Dependabot ignores updates to Go modules that do not have semantic version
tags. See: https://github.com/dependabot/dependabot-core/issues/3017.
Therefore, this change replaces dependabot with a custom workflow with
upgrades Go dependencies using `go get -u ./...` and creates a PR. This PR
will be auto-merged using the existing logic for cadobot-generated PRs.
