pin greenlet version to 3.1.0 for 3.8

.riot/requirements/1d4e95e.txt

@@ -0,0 +1,27 @@
+#
+# This file is autogenerated by pip-compile with Python 3.13
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate .riot/requirements/1d4e95e.in
+#
+attrs==24.3.0
+coverage[toml]==7.6.10
+gevent==24.11.1
+greenlet==3.1.1
+hypothesis==6.45.0
+iniconfig==2.0.0
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+packaging==24.2
+pluggy==1.5.0
+pytest==8.3.4
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pytest-randomly==3.16.0
+sortedcontainers==2.4.0
+zope-event==5.0
+zope-interface==7.2
+
+# The following packages are considered to be unsafe in a requirements file:
+setuptools==75.8.0

.riot/requirements/27d0ff3.txt → .riot/requirements/6bec1ec.txt

@@ -2,13 +2,13 @@
 # This file is autogenerated by pip-compile with Python 3.8
 # by the following command:
 #
-#    pip-compile --allow-unsafe --no-annotate .riot/requirements/27d0ff3.in
+#    pip-compile --allow-unsafe --no-annotate .riot/requirements/6bec1ec.in
 #
 attrs==24.3.0
 coverage[toml]==7.6.1
 exceptiongroup==1.2.2
 gevent==24.2.1
-greenlet==3.1.1
+greenlet==3.1.0
 hypothesis==6.45.0
 importlib-metadata==8.5.0
 iniconfig==2.0.0

riotfile.py

@@ -2943,6 +2943,17 @@ def select_pys(min_version: str = MIN_PYTHON_VERSION, max_version: str = MAX_PYT
             env={
                 "DD_AGENT_PORT": "9126",
             },
+            venvs=[
+                # Python 3.8
+                Venv(
+                    pys=["3.8"],
+                    pkgs={"greenlet": "==3.1.0"},
+                ),
+                # Python 3.9+
+                Venv(
+                    pys=select_pys(min_version="3.9"),
+                ),
+            ],
         ),
         Venv(
             name="subprocess",