chore: Use supported version of redigo

[stevenh]

Switch from 2.0 which is unsupported, created before go mod was developed to 1.8.4 which is the supported version of redigo.

Also:

• Bumped min go version to 1.17 and removed travis tests on go 1.15 and 1.16 as redigo requires context hence min version is 1.17.
• Added missing go.sum.

[wkoszek]

@elithrar @boj @kisielk @tsenart Any chance we could merge this?

One of my hobby projects is using redistore package, and I can no longer go get -u. I'm getting:

$ go get -u
go: warning: github.com/gomodule/[email protected]+incompatible: retracted by module author: Old development version not maintained or published.
go: to switch to the latest unretracted version, run:
	go get github.com/gomodule/redigo@latest

I think this PR would fix it.

[fgm]

Should probably use redigo 1.8.9 instead of 1.8.4 now, otherwise LGTM. Sending updated PR #64

[stevenh]

Yep its been a while, updated to the latest version.

[wkoszek]

@stevenh @fgm @elithrar do you stay in touch with @boj ? If we merge this, I can test it.

[stevenh]

I’m afraid I don’t. I only submitted this as it was raised as an issue in redigo which I maintain.