Update to Go 1.17

[SaschaSchwarze0]

Go 1.17 exists for a while now and the CLI is using it already. We should also update the Go version here in the build repo.

Acceptence criteria:

• go.mod has been updated, go mod vendor was run. There will be many changes as Go 1.17 changed the format of indirect dependencies
• the workflows have been updated to all use 1.17.
• HACK.md has been updated
• the ko build strategy has been updated to use Go 1.17 by default
• the sample ko build that builds shipwright has been updated to use Go 1.17

[sm43]

/assign