Update gorp dependency to gorp.v2

[JAmes]

Hi! Could I convince you to migrate from gorp.v1 to gorp.v2?

There's only one note in the migration guide: https://github.com/go-gorp/gorp#pre-v2-to-v2

[Ruben Vermeersch]

It's probably about time we do that indeed!

Could you send a PR?

[Idcmp]

#206 bumps to the latest gorp which is backwards compatible with v2.2.0 except it cleans up its go.mod handling. HTH!

[Ruben Vermeersch]

Closed in #206, thanks @idcmp

[WonSikin]

@jamesatwill-okta @rubenv
Found an issue after #206 was merged

$ go get -v github.com/rubenv/sql-migrate/...
github.com/rubenv/sql-migrate (download)
github.com/go-gorp/gorp (download)
package github.com/rubenv/sql-migrate: cannot find package "github.com/go-gorp/gorp/v3" in any of:
	/usr/local/go/src/github.com/go-gorp/gorp/v3 (from $GOROOT)
	/go/src/github.com/go-gorp/gorp/v3 (from $GOPATH)

[Lee]

@wonsikin Had the same error too. If you do export GO111MODULE=on before running go get -v github.com/rubenv/sql-migrate/... this fixes the issue.

[jojo]

@slee500 @wonsikin
I did export GO111MODULE=on before running go get -v github.com/rubenv/sql-migrate/....
But I had same error too.
My Golang version is 1.15.0.

[jojo]

I'm sorry. I had mistake.
If you do export GO111MODULE=on before running go get -v github.com/rubenv/sql-migrate/... this fixes the issue.
But I don't know this reason.

[Lee]

@jotaro-biz here's a good writeup on what export GO111MODULE=on does.
https://maelvls.dev/go111module-everywhere/