worktree: upgrade lock to an int

Author: ethomson

include/git2/worktree.h

@@ -77,7 +77,7 @@ GIT_EXTERN(int) git_worktree_validate(const git_worktree *wt);
 typedef struct git_worktree_add_options {
 	unsigned int version;
 
-	char lock; /**< lock newly created worktree */
+	int lock; /**< lock newly created worktree */
 } git_worktree_add_options;
 
 #define GIT_WORKTREE_ADD_OPTIONS_VERSION 1