Add example to S4 class git_merge_result show method

Signed-off-by: Stefan Widgren <stefan.widgren@gmail.com>
Update libgit2 source code (e06b10)

* Update libgit2 source code to commit
  e06b1040d703b4489f8280674e59b5245595c586

Signed-off-by: Stefan Widgren <stefan.widgren@gmail.com>