[gn build] Port 7b8f7be

Author: llvmgnsyncbot

llvm/utils/gn/secondary/clang-tools-extra/clang-tidy/bugprone/BUILD.gn

@@ -86,6 +86,7 @@ static_library("bugprone") {
     "SuspiciousStringviewDataUsageCheck.cpp",
     "SwappedArgumentsCheck.cpp",
     "SwitchMissingDefaultCaseCheck.cpp",
+    "TaggedUnionMemberCountCheck.cpp",
     "TerminatingContinueCheck.cpp",
     "ThrowKeywordMissingCheck.cpp",
     "TooSmallLoopVariableCheck.cpp",