v1.4.0

• Add a CMake TSL_ROBIN_MAP_ENABLE_INSTALL option to explicitly enable/disable the install target
• Move to C++17 dropping C++11 support
• Bump cmake_minimum_required version to 3.5
• Fix load threshold on deserialization
  The current version computes load using max_load_factor() without first
  setting m_bucket_count (default 0) leading to threshold 0, which
  triggers rehash (and size increase) on first insert.
  Recompute the threshold after setting correct bucket count to avoid
  this.
• Use inline constexpr for PRIMES and MOD_PRIME arrays