swap from Go Dep to Go Modules

[nicfb]

This further address issue #31

[coveralls]

Pull Request Test Coverage Report for Build 95

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

---

Totals
Change from base Build 92:	0.0%
Covered Lines:	118
Relevant Lines:	118

---

💛 - Coveralls

[nitishm]

@Shivam010 go 1.9.6 is failing with error

$ env GO111MODULE=on golangci-lint run ./...

WARN [runner/megacheck] Can't run megacheck because of compilation errors in packages [github.com/nitishm/go-rejson [github.com/nitishm/go-rejson.test] github.com/nitishm/go-rejson/clients]: doc.go:1: /tmp/gopackages956184363/go-build/net/cgo_linux.cgo1.go:1: no such file or directory and 11 more errors: run `golangci-lint run --no-config --disable-all -E typecheck` to see all errors 

doc.go:1: /tmp/gopackages956184363/go-build/net/cgo_linux.cgo1.go:1: no such file or directory (typecheck)

/*

clients/goredis.go:1: /tmp/gopackages956184363/go-build/net/cgo_linux.cgo1.go:1: no such file or directory (typecheck)

package clients

The command "env GO111MODULE=on golangci-lint run ./..." exited with 1.

[Shivam010]

@Shivam010 go 1.9.6 is failing with error

/cc https://github.com/nitishm/go-rejson/issues/31#issuecomment-518818097