build(deps): bump certifi from 2023.5.7 to 2023.7.22 in /.kokoro

Bumps [certifi](https://github.com/certifi/python-certifi) from 2023.5.7 to 2023.7.22.
- [Commits](certifi/python-certifi@2023.05.07...2023.07.22)

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

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

.kokoro/requirements.txt

@@ -12,9 +12,9 @@ cachetools==5.3.1 \
     --hash=sha256:95ef631eeaea14ba2e36f06437f36463aac3a096799e876ee55e5cdccb102590 \
     --hash=sha256:dce83f2d9b4e1f732a8cd44af8e8fab2dbe46201467fc98b3ef8f269092bf62b
     # via google-auth
-certifi==2023.5.7 \
-    --hash=sha256:0f0d56dc5a6ad56fd4ba36484d6cc34451e1c6548c61daad8c320169f91eddc7 \
-    --hash=sha256:c6c2e98f5c7869efca1f8916fed228dd91539f9f1b444c314c06eef02980c716
+certifi==2023.7.22 \
+    --hash=sha256:539cc1d13202e33ca466e88b2807e29f4c13049d6d87031a3c110744495cb082 \
+    --hash=sha256:92d6037539857d8206b8f6ae472e8b77db8058fec5937a1ef3f54304089edbb9
     # via requests
 cffi==1.15.1 \
     --hash=sha256:00a9ed42e88df81ffae7a8ab6d9356b371399b91dbdf0c3cb1e84c03a13aceb5 \
@@ -485,6 +485,5 @@ zipp==3.16.1 \
     # via importlib-metadata
 
 # WARNING: The following packages were not pinned, but pip requires them to be
-# pinned when the requirements file includes hashes and the requirement is not
-# satisfied by a package already installed. Consider using the --allow-unsafe flag.
+# pinned when the requirements file includes hashes. Consider using the --allow-unsafe flag.
 # setuptools