Remove Python version from `/_synapse/admin/v1/server_version` (#16380)

There's no reason to expose the full Python version over what is
frequently a public API.

changelog.d/16380.removal

@@ -0,0 +1 @@
+Remove Python version from `/_synapse/admin/v1/server_version`.

docs/admin_api/version_api.md

@@ -1,7 +1,7 @@
 # Version API
 
-This API returns the running Synapse version and the Python version
-on which Synapse is being run. This is useful when a Synapse instance
+This API returns the running Synapse version.
+This is useful when a Synapse instance
 is behind a proxy that does not forward the 'Server' header (which also
 contains Synapse version information).
 
@@ -15,7 +15,9 @@ It returns a JSON body like the following:
 
 ```json
 {
-    "server_version": "0.99.2rc1 (b=develop, abcdef123)",
-    "python_version": "3.7.8"
+    "server_version": "0.99.2rc1 (b=develop, abcdef123)"
 }
 ```
+
+*Changed in Synapse 1.94.0:* The `python_version` key was removed from the
+response body.

synapse/rest/admin/__init__.py

@@ -16,7 +16,6 @@
 # limitations under the License.
 
 import logging
-import platform
 from http import HTTPStatus
 from typing import TYPE_CHECKING, Optional, Tuple
 
@@ -107,10 +106,7 @@ class VersionServlet(RestServlet):
     PATTERNS = admin_patterns("/server_version$")
 
     def __init__(self, hs: "HomeServer"):
-        self.res = {
-            "server_version": SYNAPSE_VERSION,
-            "python_version": platform.python_version(),
-        }
+        self.res = {"server_version": SYNAPSE_VERSION}
 
     def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
         return HTTPStatus.OK, self.res

tests/rest/admin/test_admin.py

@@ -42,9 +42,7 @@ class VersionTestCase(unittest.HomeserverTestCase):
         channel = self.make_request("GET", self.url, shorthand=False)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
-        self.assertEqual(
-            {"server_version", "python_version"}, set(channel.json_body.keys())
-        )
+        self.assertEqual({"server_version"}, set(channel.json_body.keys()))
 
 
 class QuarantineMediaTestCase(unittest.HomeserverTestCase):