Drop python 3.8

While it is still supported by PSF, it is deprecated by numpy's policy,
which is a community standard among scientific packages.

.github/workflows/run-tests.yml

@@ -12,7 +12,6 @@ jobs:
  fail-fast: false
  matrix:
  python-version:
- - '3.8'
  - '3.9'
  - '3.10'
  igraph: ["igraph", "no-igraph"]

setup.py

@@ -41,13 +41,12 @@
  'License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)',
 
  'Programming Language :: Python :: 3',
- 'Programming Language :: Python :: 3.8',
  'Programming Language :: Python :: 3.9',
  'Programming Language :: Python :: 3.10',
  ],
  install_requires=requirements,
  extras_require={'extras': ['fuzzywuzzy[speedup]~=0.17.0',
  'ujson~=1.35']},
- python_requires='>=3.8',
+ python_requires='>=3.9',
  zip_safe=False
 )