Increase minimum supported Python version to 3.10.

From now on, Python 3.8 and 3.9 are not supported, following [SPEC
0](https://scientific-python.org/specs/spec-0000/).

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ['3.8', '3.9']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
     - uses: actions/checkout@v2

pyproject.toml

@@ -2,7 +2,7 @@
 name = "dcor"
 description = "dcor: distance correlation and energy statistics in Python."
 readme = "README.rst"
-requires-python = ">=3.8"
+requires-python = ">=3.10"
 license = {file = "LICENSE"}
 keywords = [
 	"distance correlation",
@@ -27,7 +27,9 @@ classifiers = [
     "Natural Language :: English",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
     "Topic :: Scientific/Engineering :: Mathematics",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
@@ -57,6 +59,7 @@ docs = [
 ]
 test = [
   "array-api-strict",
+  "numpy<2", # NumPy 2 changes array repr, affecting doctests.
   "pytest",
   "pytest-cov",
   "pytest-subtests",

readthedocs.yml

@@ -8,7 +8,7 @@ version: 2
 build:
   os: ubuntu-20.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx: