fix: moves packaging requirements to setup.cfg

Also moves documentation and development requirements to
targets [docs] and [dev] respectively.

docs/requirements.txt

@@ -1,2 +0,0 @@
-sphinx
-myst-nb

readthedocs.yaml

@@ -22,7 +22,9 @@ sphinx:
 # Optionally declare the Python requirements required to build your docs
 python:
    install:
-   - requirements: requirements.txt
-   - requirements: docs/requirements.txt
    - method: pip
      path: .
+     extra_requirements:
+       - .
+       - docs
+       - dev

requirements.txt

@@ -1,5 +0,0 @@
-ipykernel
-numpy
-scipy
-matplotlib
-numba

setup.cfg

@@ -17,6 +17,23 @@ package_dir =
     = src
 packages = find:
 python_requires = >=3.6
+install_requires =
+    numpy
+    scipy
+    matplotlib
+    numba
+
+[options.extras_require]
+dev =
+    pytest == 7.1
+    pytest-cov == 3.0
+    pre-commit == 2.20
+    hypothesis == 6.29
+    jupyter-lab
+docs =
+    ipykernel == 6.9.0
+    sphinx >= 4.0.0
+    myst-nb
 
 [options.packages.find]
 where = src