Fix php8.4 deprecated notices

[it-can]

Fixes

PHP Deprecated:  MathPHP\Statistics\Multivariate\PCA::standardizeData(): Implicitly marking parameter $new_data as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/Multivariate/PCA.php on line 109
PHP Deprecated:  MathPHP\Statistics\Multivariate\PCA::getScores(): Implicitly marking parameter $new_data as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/Multivariate/PCA.php on line 167
PHP Deprecated:  MathPHP\Statistics\Multivariate\PCA::getQResiduals(): Implicitly marking parameter $new_data as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/Multivariate/PCA.php on line 223
PHP Deprecated:  MathPHP\Statistics\Multivariate\PCA::getT2Distances(): Implicitly marking parameter $new_data as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/Multivariate/PCA.php on line 268
PHP Deprecated:  MathPHP\Statistics\KernelDensityEstimation::__construct(): Implicitly marking parameter $h as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/KernelDensityEstimation.php on line 52
PHP Deprecated:  MathPHP\Statistics\KernelDensityEstimation::setBandwidth(): Implicitly marking parameter $h as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/KernelDensityEstimation.php on line 71
PHP Deprecated:  MathPHP\Statistics\Distance::mahalanobis(): Implicitly marking parameter $y as nullable is deprecated, the explicit nullable type must be used instead in ./src/Statistics/Distance.php on line 194
PHP Deprecated:  MathPHP\Probability\Combinatorics::permutations(): Implicitly marking parameter $k as nullable is deprecated, the explicit nullable type must be used instead in ./src/Probability/Combinatorics.php on line 231
PHP Deprecated:  MathPHP\Functions\BaseEncoderDecoder::createArbitraryInteger(): Implicitly marking parameter $offset as nullable is deprecated, the explicit nullable type must be used instead in ./src/Functions/BaseEncoderDecoder.php on line 94
PHP Deprecated:  MathPHP\LinearAlgebra\NumericMatrix::eigenvalues(): Implicitly marking parameter $method as nullable is deprecated, the explicit nullable type must be used instead in ./src/LinearAlgebra/NumericMatrix.php on line 3032
PHP Deprecated:  MathPHP\LinearAlgebra\NumericMatrix::eigenvectors(): Implicitly marking parameter $method as nullable is deprecated, the explicit nullable type must be used instead in ./src/LinearAlgebra/NumericMatrix.php on line 3071
PHP Deprecated:  MathPHP\LinearAlgebra\MatrixFactory::eye(): Implicitly marking parameter $x as nullable is deprecated, the explicit nullable type must be used instead in ./src/LinearAlgebra/MatrixFactory.php on line 428

[coveralls]

coverage: 99.924% (+0.003%) from 99.921%
when pulling b1ccbf3 on it-can:master
into e587bfe on markrogoyski:develop.

[markrogoyski]

Thank you for your interest in MathPHP and the PHP 8.4 improvements!

I will include this in the next release in the next few days. Thanks again!