The libc++ upgrade means we can use contains() in versioner now.

Change-Id: Ie09ee136ce9d5250900ca1a2d0010814073bf1a7
diff --git a/tools/versioner/src/versioner.cpp b/tools/versioner/src/versioner.cpp
index 5afa00b..320c19c 100644
--- a/tools/versioner/src/versioner.cpp
+++ b/tools/versioner/src/versioner.cpp
@@ -142,7 +142,7 @@
 
   auto new_end = std::remove_if(headers.begin(), headers.end(), [&arch](llvm::StringRef header) {
     for (const auto& it : ignored_headers) {
-      if (it.second.find(arch) == it.second.end()) {
+      if (!it.second.contains(arch)) {
         continue;
       }