Merge pull request #600 from prometheus/dependabot/pip/tools/load-generator/urllib3-1.26.18

Bump urllib3 from 1.26.15 to 1.26.18 in /tools/load-generator

Author: SuperQ

tools/load-generator/requirements.txt

@@ -3,4 +3,4 @@ certifi==2023.7.22
 idna==3.4
 prometheus-client==0.17.0
 requests==2.28.2
-urllib3==1.26.15
+urllib3==1.26.18