chore(deps): bump certifi from 2023.7.22 to 2024.7.4 in /.kokoro

Bumps [certifi](https://github.com/certifi/python-certifi) from 2023.7.22 to 2024.7.4.
- [Commits](certifi/python-certifi@2023.07.22...2024.07.04)

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

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

.kokoro/requirements.txt

@@ -16,9 +16,9 @@ cachetools==5.3.2 \
  --hash=sha256:086ee420196f7b2ab9ca2db2520aca326318b68fe5ba8bc4d49cca91add450f2 \
  --hash=sha256:861f35a13a451f94e301ce2bec7cac63e881232ccce7ed67fab9b5df4d3beaa1
  # via google-auth
-certifi==2023.7.22 \
- --hash=sha256:539cc1d13202e33ca466e88b2807e29f4c13049d6d87031a3c110744495cb082 \
- --hash=sha256:92d6037539857d8206b8f6ae472e8b77db8058fec5937a1ef3f54304089edbb9
+certifi==2024.7.4 \
+ --hash=sha256:5a1e7645bc0ec61a09e26c36f6106dd4cf40c6db3a1fb6352b0244e7fb057c7b \
+ --hash=sha256:c198e21b1289c2ab85ee4e67bb4b4ef3ead0892059901a8d5b622f24a1101e90
  # via requests
 cffi==1.16.0 \
  --hash=sha256:0c9ef6ff37e974b73c25eecc13952c55bceed9112be2d9d938ded8e856138bcc \