Build break due to golang version on RPi

[tiokim]

Describe the bug
RPi instruction guides developers to install golang with command sudo apt install golang.
RPi install 1.11 version of golang and it fails to build the project.
Find the log below.

pi@raspberrypi:~/edge-home-orchestration-go $ go version
go version go1.11.6 linux/arm
pi@raspberrypi:~/edge-home-orchestration-go $ ./build.sh

-----------------------------------
 Install prerequisite packages
-----------------------------------
(1/7) go get -u github.com/axw/gocov/gocov: Done
(2/7) go get -u github.com/matm/gocov-html: Done
(3/7) go get -u golang.org/x/lint/golint: Done
(4/7) go get -u github.com/Songmu/make2help/cmd/make2help: Done
(5/7) go get -u golang.org/x/mobile/cmd/gomobile# golang.org/x/tools/go/packages
../go/src/golang.org/x/tools/go/packages/golist_overlay.go:547:7: undefined: strings.ReplaceAll

download fail

[tdrozdovsky]

@t25kim @MoonkiHong I faced with this issue too. We have two options:

1. Fix the version golang.org/x/mobile/cmd/gomobile in glide.yaml
2. Download the new version of Go and raise the requirements for the Go version in the documentation to 1.12. (I successfully made this option)

[MoonkiHong]

@t25kim @MoonkiHong I faced with this issue too. We have two options:

1. Fix the version golang.org/x/mobile/cmd/gomobile in glide.yaml
2. Download the new version of Go and raise the requirements for the Go version in the documentation to 1.12. (I successfully made this option)

@tdrozdovsky Please refer to the recent document update for build in terms of Go version (targeting x86_64). (1.10 -> 1.15)

[tdrozdovsky]

@MoonkiHong The go 1.15 version also works good. I will prepare changes to the documentation for raspberry Pi and prepare a PR