Out of bound error in gut squash

[Julien C]

Describe the bug
Gut returns this when running gut squash

panic: runtime error: slice bounds out of range [:-1]

goroutine 1 [running]:
github.com/julien040/gut/src/controller.Squash.func1(...)
        /Users/julien/Code/gut/src/controller/squash.go:98
github.com/julien040/gut/src/controller.Squash(0x14000125000?, {0x10348ce20, 0x0, 0x102e7072b?})
        /Users/julien/Code/gut/src/controller/squash.go:120 +0x8d4
github.com/spf13/cobra.(*Command).execute(0x103405960, {0x10348ce20, 0x0, 0x0})
        /Users/julien/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:920 +0x640
github.com/spf13/cobra.(*Command).ExecuteC(0x103404de0)
        /Users/julien/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:1044 +0x320
github.com/spf13/cobra.(*Command).Execute(...)
        /Users/julien/go/pkg/mod/github.com/spf13/cobra@v1.6.1/command.go:968
github.com/julien040/gut/cmd.Execute()
        /Users/julien/Code/gut/cmd/root.go:50 +0x28
main.main()
        /Users/julien/Code/gut/main.go:27 +0x1c

To Reproduce
Steps to reproduce the behavior:

1. Create a repo with exactly two commits
2. Don't push any of them to the remote
3. Run gut squash

Expected behavior
squash should be able to squash the first two commits into one.

Desktop (please complete the following information):

• OS: macOS
• Version 0.2.10

[Julien C]

This is due to not handling this -1 in this function (src/controller/squash.go)

func getIndexLatestCommitPushed(commits []object.Commit) int {
	for i, commit := range commits {
		if executor.GitRemoteContainsHash(commit.Hash.String()) {
			return i
		}
	}
	return -1
}

-1 happens when no commits have been pushed so far.