environment.h: move declarations for environment.c functions from cache.h

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/notes-utils.c b/notes-utils.c
index da08e2e..8797271 100644
--- a/notes-utils.c
+++ b/notes-utils.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "commit.h"
+#include "environment.h"
 #include "gettext.h"
 #include "refs.h"
 #include "notes-utils.h"