Update protobuf
Disabled leak sanitizer on travis, looks like travis removed SYS_PTRACE.
diff --git a/.travis.yml b/.travis.yml
index 58d5338..a570894 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -57,5 +57,6 @@
   - cmake .. -GNinja -DLIB_PROTO_MUTATOR_WITH_ASAN=ON -DLIB_PROTO_MUTATOR_DOWNLOAD_PROTOBUF=ON -DCMAKE_C_COMPILER=${CC_COMPILER} -DCMAKE_CXX_COMPILER=${CXX_COMPILER} -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DLIB_PROTO_MUTATOR_CTEST_JOBS=8
 
 script:
+  - export ASAN_OPTIONS=detect_leaks=0
   - ninja
   - ninja check