ResetDefaultToCommit maps git_reset_default

Added support for default reset behavior

reset.go

@@ -24,3 +24,19 @@ func (r *Repository) ResetToCommit(commit *Commit, resetType ResetType, opts *Ch
 	}
 	return nil
 }
+
+func (r *Repository) ResetDefaultToCommit(commit *Commit, pathspecs []string) error {
+	cpathspecs := C.git_strarray{}
+	cpathspecs.count = C.size_t(len(pathspecs))
+	cpathspecs.strings = makeCStringsFromStrings(pathspecs)
+	defer freeStrarray(&cpathspecs)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	ret := C.git_reset_default(r.ptr, commit.ptr, &cpathspecs)
+
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}