nanoflann 1.12.0

• Merge pull request #312 from jlblancoc/feat/automate-release-script
  automate release to ensure consistency
• automate release to ensure consistency
• fix: stop asserting exact NN index in bruteforce comparison tests
  Two points can be equidistant (or within float rounding) from a query;
  nanoflann does not guarantee a tie-break order unless
  NANOFLANN_FIRST_MATCH is defined, so comparing indices makes these
  tests flaky whenever a near-tie occurs. Checking the returned distance
  against the brute-force minimum already fully validates correctness.
• Merge pull request #311 from jlblancoc/fix-potential-ram-run
  fix: ensure background rebuild spans one single thread
• address review
• fix: ensure background rebuild spans one single thread
• Merge pull request #310 from jlblancoc/feat/install-examples-option
  Add opt-in NANOFLANN_INSTALL_EXAMPLES option
• Add opt-in NANOFLANN_INSTALL_EXAMPLES option
  Lets users who need the example binaries installed opt in via CMake,
  without changing default behavior for the header-only library.
• Contributors: Jose Luis Blanco-Claraco