Fix for env variable.

[enrichman]

This PR fix a bug occuring during the parsing of the env variables

-> % epinio app create --env "BP_GO_BUILD_LDFLAGS=-X main.Version=myVersion" -- samplego
unable to get app configuration: Bad --env assignment `BP_GO_BUILD_LDFLAGS=-X main.Version=myVersion`, expected `name=value` as value

There was a check that an env option should be splitted in exactly two, divided by a = sign.
This was failing trying to set a variable like this VAR=foo=bar, it was not possible to set the value of foo=bar to VAR.

environment := models.EnvVariableMap{}
for _, assignment := range evAssignments {
	pieces := strings.Split(assignment, "=")
	if len(pieces) != 2 {
		return manifest, errors.New("Bad --env assignment `" + assignment + "`, expected `name=value` as value")
	}
	environment[pieces[0]] = pieces[1]
}

Moved the strings.Split to a strings.SplitN(s, sep, 2) so we can split at most at two values.

environment := models.EnvVariableMap{}
for _, assignment := range evAssignments {
	pieces := strings.SplitN(assignment, "=", 2)
	if len(pieces) < 2 {
		return manifest, errors.New("Bad --env assignment `" + assignment + "`, expected `name=value` as value")
	}
	environment[pieces[0]] = pieces[1]
}

I've also renamed the UpdateISE to UpdateICE, and refactored the UpdateICE and the UpdateBSN splitting the three logic in different functions.

note

I don't feel that we should pass the cobra.Command, the manifest package should probably just perform logic on the manifest and should not be aware of where the values are coming from, but I didn't want to change too many things.

I'm available to move that logic though. :)

[andreas-kupries]

LTGM. The only nit I have is that there is no cli test demonstrating a complex --env where the changed split makes the difference. Not a blocker tough.