Set clang-format standard to C++11 (#1820)

.clang-format

@@ -1,7 +1,7 @@
 # http://clang.llvm.org/docs/ClangFormatStyleOptions.html
 
 BasedOnStyle: Google
-Standard: Cpp03
+Standard: c++11
 AllowShortFunctionsOnASingleLine: Empty
 IncludeBlocks: Preserve
 IndentPPDirectives: AfterHash

src/ArduinoJson/Object/JsonObject.hpp

@@ -108,8 +108,8 @@ class JsonObject : public detail::VariantOperators<JsonObject> {
   // Gets or sets the member with specified key.
   // https://arduinojson.org/v6/api/jsonobject/subscript/
   template <typename TString>
-  FORCE_INLINE typename detail::enable_if<
-      detail::IsString<TString>::value,
+  FORCE_INLINE
+      typename detail::enable_if<detail::IsString<TString>::value,
                                  detail::MemberProxy<JsonObject, TString>>::type
       operator[](const TString& key) const {
     return {*this, key};