build(deps): bump jinja2 in /.kokoro in the pip group across 1 directory

Bumps the pip group with 1 update in the /.kokoro directory: [jinja2](https://github.com/pallets/jinja).


Updates `jinja2` from 3.1.4 to 3.1.5
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/main/CHANGES.rst)
- [Commits](pallets/jinja@3.1.4...3.1.5)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.kokoro/requirements.txt

@@ -327,9 +327,9 @@ jeepney==0.8.0 \
     # via
     #   keyring
     #   secretstorage
-jinja2==3.1.4 \
-    --hash=sha256:4a3aee7acbbe7303aede8e9648d13b8bf88a429282aa6122a993f0ac800cb369 \
-    --hash=sha256:bc5dd2abb727a5319567b7a813e6a2e7318c39f4f487cfe6c89c6f9c7d25197d
+jinja2==3.1.5 \
+    --hash=sha256:8fefff8dc3034e27bb80d67c671eb8a9bc424c0ef4c0826edbff304cceff43bb \
+    --hash=sha256:aba0f4dc9ed8013c424088f68a5c226f7d6097ed89b246d7749c2ec4175c6adb
     # via gcp-releasetool
 keyring==24.2.0 \
     --hash=sha256:4901caaf597bfd3bbd78c9a0c7c4c29fcd8310dab2cffefe749e916b6527acd6 \