'go get' doesn't work, use 'go install' instead

[vucefalas]

The following doesn't work:

$ go get github.com/gcash/bchwallet
go: go.mod file not found in current directory or any parent directory.
        'go get' is no longer supported outside a module.
        To build and install a command, use 'go install' with a version,
        like 'go install example.com/cmd@latest'
        For more information, see https://golang.org/doc/go-get-install-deprecation
        or run 'go help get' or 'go help install'.

The recommended way is to use 'go install', however the following error occurs when trying this:

$ go install github.com/gcash/bchwallet@latest
go: downloading github.com/gcash/bchwallet v0.10.0
go: github.com/gcash/bchwallet@latest (in github.com/gcash/bchwallet@v0.10.0):
        The go.mod file for the module providing named packages contains one or
        more replace directives. It must not contain directives that would cause
        it to be interpreted differently than if it were the main module.