Switch httpcore2 from certifi to truststore for default SSL verification

src/httpcore2/httpcore2/_ssl.py

@@ -1,9 +1,12 @@
+import os
 import ssl
 
-import certifi
+import truststore
 
 
 def default_ssl_context() -> ssl.SSLContext:
-    context = ssl.create_default_context()
-    context.load_verify_locations(certifi.where())
-    return context
+    if cafile := os.environ.get("SSL_CERT_FILE"):  # pragma: no cover
+        return ssl.create_default_context(cafile=cafile)
+    if capath := os.environ.get("SSL_CERT_DIR"):  # pragma: no cover
+        return ssl.create_default_context(capath=capath)
+    return truststore.SSLContext(ssl.PROTOCOL_TLS_CLIENT)

src/httpcore2/pyproject.toml

@@ -41,7 +41,7 @@ classifiers = [
     "Programming Language :: Python :: 3.14",
     "Topic :: Internet :: WWW/HTTP",
 ]
-dependencies = ["certifi", "h11>=0.16"]
+dependencies = ["truststore>=0.10", "h11>=0.16"]
 
 [project.optional-dependencies]
 http2 = ["h2>=3,<5"]