Commands.Stage() fails with a submodule

Reproduction steps

1. Add a submodule to a Git repository like git submodule add ../test-module test-module
2. Change the commit of the submodule like cd test-module; git checkout -b branch-name
3. Try to stage the submodule using libgit2sharp with Commands.Stage("*") or with Commands.Stage("test-module")

Expected behavior

The submodule change should be staged.

Actual behavior

An exception is thrown because git_index_add_bypath() failed because the path is invalid: test-module/

Commands.Stage() adds a slash at the end of the submodule name it passes to git_index_add_bypath which causes it to fail. git_index_add_bypath works fine passing it test-module directly with repo.Index.Add("test-module") (which is a workaround I'll use for now).

Version of LibGit2Sharp (release number or SHA1)

LibGit2Sharp 0.26.2

Operating system(s) tested; .NET runtime tested

.NET Framework 4.7.2 on Windows 10

从 Commands.Stage 入口点开始，使用 Commands.Stage("*") 和 Commands.Stage("test-module") 重现所述的子模块情况。将其路径处理与被报告为 workaround 的 repo.Index.Add("test-module") 进行比较。完成标准是能够在没有尾部斜杠路径错误的情况下暂存已更改的子模块。