Make clang-tidy check header files too (#2072)

aheejin · web-flow · commit fba743ca5bdf · 2019-04-30T17:51:03.000-07:00
Without this header file errors would be ignored.
diff --git a/.clang-tidy b/.clang-tidy
@@ -14,3 +14,4 @@ CheckOptions:
     value:           camelBack
   - key:             readability-identifier-naming.VariableCase
     value:           camelBack
+HeaderFilterRegex: src/*
