nloptr 2.2.0

This release fixes a breaking bug which affects nloptr and its reverse dependencies and brings some minor tweaks and corrections along the way:

• Minimal patch for build against nlopt 2.9.x (#176, @jaganmn): specifically, the issuses were that (i) nlopt versions 2.9.x had one less algorithm in the enum list, namely NLOPT_LD_LBFGS_NOCEDAL was removed in these versions and put back in 2.10 and (ii) we were using inst/include in which we copied nlopt headers conditionally to build the package (e.g. listing it in PKG_CPPFLAGS) resulting in possible version conflicts.
• Fix the 2 failed tests by adding one more termination criterion.
• Update GHA workflows to latest versions.
• Fix reverse LinkingTo dependencies by (i) unconditionally copying headers to inst/include and (ii) fixing cmake path search (#179, @astamm).
• Fix for newly broken kergp package due to wrong usage of if statement inside paste() which works differently than when used inside c() (#180, @astamm).
• Update artifact action to v4 (#174, @eddelbuettel).
• Correcting some of the unit tests in test-banana (#167, @aadler).
• Correcting some of the unit tests in test-global-wrapper (#166, @aadler).
• Update the code in nloptr.c for compatibility with the R API, efficiency,
  and formatting (#169, @aadler).
• Bugfix: ranseed expects an unsigned long but was passed as an integer, thus
  reducing the range of random seeds. It is now passed as a double and converted
  to a long (#169, @aadler).