Redis 6.2 image for CI

[TonyCTHsu]

What does this PR do?

Use Redis 6.2 image for CI. This would allow us to gradually testing newer gem version of redis and sidekiq

1. Align the images used for CI and development. 6.2 for new versions of redis and 3.0 for older version.
2. Since qless is having issues with newer versions of redis. Establish a new old redis container for it. We should move qless to contrib-old in future. Because the gem is not actively maintained and has a couple of dependencies that are blocking other gems in the same appraisal group.
3. Fixing failing spec, due to slightly different error message from DB redis.

[codecov-commenter]

Codecov Report

Merging #2364 (86ec11b) into master (b478593) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2364   +/-   ##
=======================================
  Coverage   98.34%   98.34%           
=======================================
  Files        1101     1101           
  Lines       58921    58924    +3     
=======================================
+ Hits        57943    57951    +8     
+ Misses        978      973    -5     

Impacted Files	Coverage Δ
spec/datadog/tracing/contrib/qless/support/job.rb	94.28% <100.00%> (ø)
spec/datadog/tracing/contrib/redis/redis_spec.rb	99.50% <100.00%> (ø)
...ng/contrib/active_support/cache/instrumentation.rb	87.67% <0.00%> (+0.08%)	⬆️
spec/datadog/profiling/native_extension_spec.rb	97.87% <0.00%> (+1.06%)	⬆️
lib/datadog/core/diagnostics/environment_logger.rb	100.00% <0.00%> (+1.57%)	⬆️
...adog/tracing/contrib/sidekiq/client_tracer_spec.rb	100.00% <0.00%> (+2.08%)	⬆️
lib/datadog/core/workers/polling.rb	100.00% <0.00%> (+3.44%)	⬆️

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[ivoanjo]

Looks good but please remember to squash the history before merging so that a bunch of WIP commits and similar don't end up on master