Update .clang-tidy to ignore benchmark::RegisterBenchmark

<snip>arborx/benchmarks/bvh_driver/benchmark_registration.hpp:383:7:
    warning: redundant call to 'c_str' [readability-redundant-string-cstr]
      spec.create_label_construction(description).c_str(),

benchmark switched to using std::string only in 1.8. As right now we
require 1.5.4, we disable this check.

.clang-tidy

@@ -1,5 +1,5 @@
 ---
-Checks:          'clang-diagnostic-*,clang-analyzer-*,-*,performance-*,-performance-inefficient-string-concatenation,mpi-*,modernize-*,-modernize-pass-by-value,-modernize-use-trailing-return-type,-modernize-avoid-c-arrays,-modernize-use-nodiscard,-modernize-concat-nested-namespaces,readability-*,-readability-braces-around-statements,-readability-named-parameter,-readability-magic-numbers,-readability-uppercase-literal-suffix,-readability-identifier-length,-readability-function-cognitive-complexity'
+Checks:          'clang-diagnostic-*,clang-analyzer-*,-*,performance-*,-performance-inefficient-string-concatenation,mpi-*,modernize-*,-modernize-pass-by-value,-modernize-use-trailing-return-type,-modernize-avoid-c-arrays,-modernize-use-nodiscard,-modernize-concat-nested-namespaces,readability-*,-readability-braces-around-statements,-readability-named-parameter,-readability-magic-numbers,-readability-uppercase-literal-suffix,-readability-identifier-length,-readability-function-cognitive-complexity,-readability-redundant-string-cstr'
 WarningsAsErrors: ''
 HeaderFilterRegex: '.*'
 AnalyzeTemporaryDtors: false

benchmarks/CMakeLists.txt

@@ -1,5 +1,7 @@
 find_package(Boost 1.56.0 REQUIRED COMPONENTS program_options)
 
+# FIXME: when we start requiring benchmark >= 1.8.0, reenable
+# "readability-redundant-string-cstr" check in .clang-tidy
 find_package(benchmark 1.5.4 REQUIRED)
 message(STATUS "Found benchmark: ${benchmark_DIR} (version \"${benchmark_VERSION}\")")