Increase itertools dependency lower bound to 0.15.0

Signed-off-by: mulhern <amulhern@redhat.com>

Author: mulkieran

Cargo.lock

@@ -119,7 +119,7 @@ version = "2.7.0"
 optional = true
 
 [dependencies.itertools]
-version = "0.14.0"
+version = "0.15.0"
 optional = true
 
 [dependencies.libblkid-rs]