* pr/19902:
  Upgrade to Testcontainers 1.12.5

Closes gh-19902

See gh-19902

Closes gh-19928

* pr/19913:
  Upgrade CI images to Ubuntu Bionic 20200112

Closes gh-19913

See gh-19913

Closes gh-19903

Closes gh-19645

* pr/19880:
  Polish "Close TomcatMetrics on shutdown for cleanup"
  Close TomcatMetrics on shutdown for cleanup

Closes gh-19880

See gh-19880

See micrometer-metrics/micrometer#1424
See gh-19880

Closes gh-19639

* pr/19776:
  Test the Gradle Plugin against Gradle 6.1

Closes gh-19776

See gh-19776

Closes gh-19872

* pr/19855:
  Polish "Encourage use of SpringBootApplication"
  Encourage use of SpringBootApplication

Closes gh-19855

See gh-19855

See gh-19855

Closes gh-19856

Closes gh-19869

Closes gh-19857

Closes gh-19842

This commit removes references of cache infra following the move to
Micrometer. We no longer ships an infinispan specific binder so the
dependency has been removed as well.

Closes gh-19838

Fixes gh-19821

* pr/19819:
  Polish "Document RedisCacheManagerBuilderCustomizer"
  Document RedisCacheManagerBuilderCustomizer

Closes gh-19819

See gh-19819

See gh-19819

This reverts commit 487b9cbf.

Fixes gh-19788

Closes gh-19783

Closes gh-19763 in 2.2.4

Closes gh-19763

Closes gh-19795

Closes gh-19799

Closes gh-19710

Closes gh-19778

Fixes gh-19520

The release didn't happen in time for 2.2.3.

See gh-19645