Dotenv parsing errors should show filename

[hanikesn]

Description

Recently we had to debug the following error in a moderately complex compose setup:

line xx: unexpected character "{" in variable name "{"

It later turned out to be a syntax error in one of the .env files included. It would have been very helpful if the error would also shown the affected file. The error originates here:

https://github.com/compose-spec/compose-go/blob/d2fae8edbd9fa258520dc2aa85399bb74819bc52/dotenv/parser.go#L130

And this seems to be the call site:

compose/cmd/compose/compose.go

Lines 676 to 679 in 66a4716

	envFromFile, err := dotenv.GetEnvFromFile(composegoutils.GetAsEqualsMap(os.Environ()), options.EnvFiles)
	if err != nil {
	return nil
	}

[ndeloof]

Indeed, would you like to contribute and propose a Pull Request on https://github.com/compose-spec/compose-go to improve this ?