chore: update requirements.txt to address dependabot security alerts. (#1957) (#1590)

Source-Link: googleapis/synthtool@e451548
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-java:latest@sha256:d13de1a4faec2645bda630b7a9aa080ce95182795aeab6f37ed4bd18cf5facbc

Co-authored-by: Owl Bot 

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
-  digest: sha256:25b384ee1674eda3984ec41c15b514a63bbeb5eda4d57c73c7e6f5adef2fd2f1
-# created: 2024-04-05T19:12:34.133475268Z
+  digest: sha256:d13de1a4faec2645bda630b7a9aa080ce95182795aeab6f37ed4bd18cf5facbc
+# created: 2024-04-24T14:22:15.892514394Z