Compilation instructions outdated

[th0rgall]

There are a few issues in the instructions.

Context:

• as instructed, I installed go and set the GOPATH variable. I then followed the rest of the steps.
• go version go1.17.2 darwin/amd64, which is the one downloadable from the Go site at the time of writing.

1st issue: deprecation warning when installing esc using the latest go

mailslurper % go get github.com/mjibson/esc
go: downloading github.com/mjibson/esc v0.2.0
go: downloading github.com/pkg/errors v0.9.1
go: downloading golang.org/x/tools v0.0.0-20190608022120-eacb66d2a7c3
go get: installing executables with 'go get' in module mode is deprecated.
	To adjust and download dependencies of the current module, use 'go get -d'.
	To install using requirements of the current module, use 'go install'.
	To install ignoring the current module, 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'.
go get: added github.com/mjibson/esc v0.2.0

The esc repo now mentions the command go get -u github.com/mjibson/esc as installation instruction, that that one also generates a deprecation warning.

2nd issue: mention that $GOPATH/bin should be added to the $PATH

Otherwise, this happens when running go generate:

mailslurper % go generate
mailslurper.go:5: running "esc": exec: "esc": executable file not found in $PATH
mailslurper % ls

3rd issue: not all Go versions >= Go 1.10 are supported

As mentioned, started with the default version go version go1.17.2 darwin/amd64
This resulted in a long sigpanic error, I think originating from esc

thor@Thors-MBP go % mailslurper
fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb01dfacedebac1e pc=0x7fff20409c9e]

runtime stack:
runtime: unexpected return pc for runtime.sigpanic called from 0x7fff20409c9e
[ many lines omitted]

Version 1.10.7 gave another issue:

mailslurper % go1.10.7 get
package github.com/labstack/echo/v4/middleware: cannot find package "github.com/labstack/echo/v4/middleware" in any of:
	/Users/thor/sdk/go1.10.7/src/github.com/labstack/echo/v4/middleware (from $GOROOT)
	/Users/thor/Code/go/src/github.com/labstack/echo/v4/middleware (from $GOPATH)
mailslurper % go1.10.7 generate
mailslurper % go1.10.7 build

Version 1.11 too:

thor@Thors-MBP mailslurper % go1.11 get
go: finding github.com/labstack/echo v3.3.10+incompatible
go build github.com/mailslurper/mailslurper/pkg/auth/authscheme: module requires Go 1.13
go build github.com/mattn/go-isatty: module requires Go 1.12
go build github.com/labstack/gommon/bytes: module requires Go 1.12
go build github.com/labstack/gommon/random: module requires Go 1.12
go build github.com/mailslurper/mailslurper/pkg/auth/auth: module requires Go 1.13
go build golang.org/x/sys/unix: module requires Go 1.12
go build github.com/mailslurper/mailslurper/pkg/cache: module requires Go 1.13
go build github.com/mailslurper/mailslurper/cmd/mailslurper/www: module requires Go 1.13

Finally, I could get all get, generate and build steps working with version 1.13!

go install golang.org/dl/go1.13@latest
go1.13 download
cd mailslurper/cmd/mailslurper
go1.13 get
go1.13 generate
go1.13 build

4th issue: mention how to run this

$ mailslurper

All this may be obvious to people with Go experience, but not to people like me who only installed Go to get started with MailSlurper.

[gaeljw]

Same here :)