subprojects: ignore redirected wrap files

We shouldn't have wrap-redirect files committed.

Change-Id: I6ae7c14ecc3edf3d9a11f6efd281c005afd7a05a
Signed-off-by: Peter Foley <pefoley@google.com>
diff --git a/.gitignore b/.gitignore
index 8b0c636..955db77 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,8 @@
 /build*/
 /subprojects/*
 !/subprojects/*.wrap
+subprojects/CLI11.wrap
+subprojects/boost.wrap
+subprojects/function2.wrap
+subprojects/googletest.wrap
+subprojects/stdplus.wrap