chore(deps): update dependency virtualenv to v20.29.2 (#568)

Author: renovate-bot

.kokoro/requirements.txt

@@ -631,9 +631,9 @@ urllib3==2.2.3 \
     # via
     #   requests
     #   twine
-virtualenv==20.28.0 \
-    --hash=sha256:23eae1b4516ecd610481eda647f3a7c09aea295055337331bb4e6892ecce47b0 \
-    --hash=sha256:2c9c3262bb8e7b87ea801d715fae4495e6032450c71d2309be9550e7364049aa
+virtualenv==20.29.2 \
+    --hash=sha256:fdaabebf6d03b5ba83ae0a02cfe96f48a716f4fae556461d180825866f75b728 \
+    --hash=sha256:febddfc3d1ea571bdb1dc0f98d7b45d24def7428214d4fb73cc486c9568cce6a
     # via nox
 wheel==0.45.1 \
     --hash=sha256:661e1abd9198507b1409a20c02106d9670b2576e916d58f520316666abca6729 \