Update vmpooler to 3.9.1 (rate limiter middleware fix) and bump chart to 3.10.2

[smahima27]

Summary

Bumps vmpooler from 3.9.0 to 3.9.1 in docker/Gemfile.lock.

Changes

• docker/Gemfile.lock: vmpooler 3.9.0 → 3.9.1
• helm-charts/vmpooler/Chart.yaml: chart version 3.10.1 → 3.10.2
• CHANGELOG.md: add 3.10.2 entry

Why

vmpooler 3.9.1 fixes a bug where the RateLimiter Rack middleware was defined but never wired into the Rack stack, meaning rate limiting had no effect even when rate_limiting_enabled: true was set in config.

Fix in puppetlabs/vmpooler#696:

# lib/vmpooler/api.rb
%w[helpers dashboard v3 request_logger healthcheck rate_limiter].each do |lib| ...
use Vmpooler::API::RateLimiter, redis, config if config[:config]['rate_limiting_enabled']