Add support for Python 3.15 (#432)

* Declare Python 3.15 support

* Test on Python 3.15

* Use 3.15-dev in CI

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8357b9b..35e13a6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,6 +34,7 @@
         - "3.12"
         - "3.13"
         - "3.14"
+        - "3.15-dev"
     steps:
     - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
     - name: Set up Python ${{ matrix.python-version }}

setup.py

diff --git a/setup.py b/setup.py
index 66bf91d..a963d0c 100755
--- a/setup.py
+++ b/setup.py
@@ -56,6 +56,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
     ],
     project_urls={
         "Source": "https://github.com/certifi/python-certifi",