Create .gitignore file

[gustoliveira]

I ran test coverage to this project and notice the coverage.out file was available to commit.

With this in mind, this pull request adds a .gitignore file to the project, which was previously missing.

[lithammer]

How did you specifically run test coverage? Given that you can pick any name I'm not sure how relevant a .gitignore file with *.out is?

$ go test -coverprofile=coverage
$ go tool cover -html=coverage

I'm also not a fan of generic ignore files that contains a bunch of entries not even relevant for the project. For example this is a library, so *.exe will never be relevant.

[lithammer]

Remove all the irrelevant entries.

Suggested change

	### Go ###
	# Binaries for programs and plugins
	*.exe
	*.exe~
	*.dll
	*.so
	*.dylib
	# Test binary, built with `go test -c`
	*.test
	# Output of the go coverage tool, specifically when used with LiteIDE
	*.out
	# Dependency directories (remove the comment below to include it)
	# vendor/
	# Go workspace file
	go.work
	# Go coverage tool.
	/*.out