Add numpy as a build requirement

Closes #39 (closed)

As described in the issue, this MR adds a pyproject.toml file that specifies "numpy>=1.14" as a build requirement.

Additional changes:

• Replace the deprecated np.typeDict alias with np.scitypeDict
• Fix new PyLint errors that appeared in newer versions of PyLint.

Notes:

• This allows sortednp to be installed via pip (e.g. pip install path/to/sortednp-repository), though I have only tested it within a clean venv running Python 3.10.11 and Pip 23.0.1.

  ❯ python -m venv .venv
  ❯ source .venv/bin/activate
  ❯ python --version      
  Python 3.10.11
  ❯ pip --version         
  pip 23.0.1 from (path truncated)/sortednp/.venv/lib/python3.10/site-packages/pip (python 3.10)
  ❯ pip list | grep setuptools
  setuptools 65.5.0
  ❯ pip install .
  (...truncated)
  Collecting numpy>=1.14
    Using cached numpy-1.26.1-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (18.2 MB)
  Building wheels for collected packages: sortednp
    Building wheel for sortednp (pyproject.toml) ... done
    Created wheel for sortednp: (...truncated)
  Installing collected packages: numpy, sortednp
  Successfully installed numpy-1.26.1 sortednp-0.4.0

• This has not been tested with installation via setup.py, or for Python versions other than 3.10.11.