build(deps): bump jinja2 from 3.1.5 to 3.1.6 in /.kokoro

Bumps [jinja2](https://github.com/pallets/jinja) from 3.1.5 to 3.1.6.
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/main/CHANGES.rst)
- [Commits](pallets/jinja@3.1.5...3.1.6)

---
updated-dependencies:
- dependency-name: jinja2
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.kokoro/requirements.txt

@@ -258,9 +258,9 @@ jeepney==0.8.0 \
     # via
     #   keyring
     #   secretstorage
-jinja2==3.1.5 \
-    --hash=sha256:8fefff8dc3034e27bb80d67c671eb8a9bc424c0ef4c0826edbff304cceff43bb \
-    --hash=sha256:aba0f4dc9ed8013c424088f68a5c226f7d6097ed89b246d7749c2ec4175c6adb
+jinja2==3.1.6 \
+    --hash=sha256:0137fb05990d35f1275a587e9aee6d56da821fc83491a0fb838183be43f66d6d \
+    --hash=sha256:85ece4451f492d0c13c5dd7c13a64681a86afae63a5f347908daf103ce6d2f67
     # via gcp-releasetool
 keyring==25.4.1 \
     --hash=sha256:5426f817cf7f6f007ba5ec722b1bcad95a75b27d780343772ad76b17cb47b0bf \