Log Message:
(math/R-nloptr) 2.0.3 to 2.1.1

# nloptr 2.1.1

This is a patch release to work around a bug in the CRAN checks. Specifically,
one of the unit tests for the `isres()` algorithm was failing on some CRAN
builds because convergence is stochastic with slightly different results even
with the same fixed seed prior to calling the function.

# nloptr 2.1.0
This release deprecates the default behavior of the inequality equations in any
wrapper function which uses them. Currently, they are calibrated to be >= 0.
This version allows for the equations to be consistent with the main `nloptr`
function, which requires <= 0. In a future release, the default behavior will
switch to assuming the calibration is <= 0, and eventually, the >= 0 behavior
will be removed. It also includes a large number of safety and efficiency
changes, and an expansion of the unit tests to 100% coverage for all files but
one. The major changes include:

* Reversed the direction of the inequality equations `hin` and `hinjac` in the
wrapper functions which use them, bringing them into compliance with the main
`nloptr` call. This addresses
[Issue #148](https://github.com/astamm/nloptr/issues/148);
* Cleaned the Hock-Schittkowski problem no. 100, Hartmann 6-dimensional, and
Powell exponential examples. This addresses
[Issue #152](https://github.com/astamm/nloptr/issues/152) and
[Issue #156](https://github.com/astamm/nloptr/issues/156);
* Updated roxygen version;
* Updated maintainer email;
* Deal with NA returns from `parallel::detectCores()` (contributed by @jeroen in
PR #150);
* Setup rhub v2 checks;
* Update cmake installation instructions on Mac with brew (#146);
* Allow use of equality constraints with COBYLA (#135);
* Replaced the unit testing framework of `testthat` with `tinytest` (See
[Issue #136](https://github.com/astamm/nloptr/issues/136));
* Brought coverage of `is.nloptr` to 100%. The only file not completely covered
by unit tests is `nloptr.c`. The uncovered calls are error messages which get
trapped by tests in R before the call gets to C;
* Linted package for code correctness and consistency;
* Updated vignette, DESCRIPTION, and NEWS;
* Updated package website to use bootstrap 5;
* Expanded unit tests: coverage now over 97% with no file below 90%;
* Removed forcing `C++11`;
* Added safety checks to C code;
* Added many safety and efficiency enhancements to R code;
* Most R code style made self-consistent;
* Updated documentation and messages for accuracy and mathematical formatting
* Updated Github actions;
* Some bugfixes (e.g. in `isres` or the warning in `nl.grad`).