See gh-20530

See gh-20530

* pr/20530:
  Polish "Automate Docker update in CI"
  Automate Docker updates in CI

Closes gh-20530

See gh-20530

See gh-20530

Closes gh-20719

This commit is a follow-up of gh-20709 to apply the same consistency
level to the Cassandra reactive health indicator.

Closes gh-20713

* pr/20709:
  Polish "Use LOCAL_ONE when querying system.local"
  Use LOCAL_ONE when querying system.local

Closes gh-20709

See gh-20709

The system keyspace has a replication factor of 1 and is local to each
node; it is therefore recommended to query system.local with a
consistency level of ONE or LOCAL_ONE.

Stronger consistency levels may result in an Unavailable error, but this
does not mean that the node is down.

See gh-20709

Previously, a condition checked the value of "spring.datasource.url" to
determine if an embedded database has to be created as a fallback. When
the value is set with an unresolved placeholder, this fails even if
the DataSource is going to created by another mean ultimately.

This commit makes a more conservative check by only checking the
presence of the property rather than its value.

Closes gh-20438

Closes gh-20624

Closes gh-19564

Previously, the presence of a `ConsumerFactory` bean would make the
auto-configured one to back off, leading to a failure down the line if
no available instance matches the generics criterion. This commit
improves the auto-configuration to create a `ConsumerFactory<?,?>`
behind the scenes if none is available.

Closes gh-19221

* gh-20583:
  Link to correct factory in TomcatReactiveWebServerFactory's javadoc

Closes gh-20583

See gh-20583

* gh-20577:
  Only suggest Ubuntu versions available in the Docker registry

Closes gh-20577

See gh-20577

This reverts commit d25286c5

Closes gh-20566

* pr/20566:
  Upgrade CI images to Ubuntu Bionic 20200311

Closes gh-20566

See gh-20566

Fixes gh-20531

Previously, DependencyCustomizer's ifAllResourcesPresent method
would return a customizer that added modules if any of the resources
were present. This commit corrects this behaviours so that modules are
only added if all resources are present.

Fixes gh-20418

TomcatReactiveWebServerFactory's getTomcatWebServer is described as
being a hook point the can be overrideden to return a different
TomcatWebServer or to apply additional processing to the Tomcat
server. Previously, this did not work as the method was not called
to create the TomcatWebServer instance. Instead, TomcatWebServer was
instantiated and returned directly.

This commit updates TomcatReactiveWebServerFactory to call
getTomcatWebServer to create the TomcatWebServer instance. A test
has also been added to verify that the method is now used.

Fixes gh-20386

This reverts commit 6828a15d.
The commit has been reverted as it breaks backwards compatiblity.

Fixes gh-20343

* pr/20420:
  Upgrade CI to Docker 19.03.7

Closes gh-20420

See gh-20420

* pr/20361:
  Upgrade CI images to Ubuntu Bionic 20200219

Closes gh-20361

See gh-20361

* pr/20355:
  Automate Ubuntu base image upgrade

Closes gh-20355

See gh-20355

Closes gh-20322

Closes gh-20321

Closes gh-20320

Closes gh-20198

Closes gh-20197

Closes gh-20196

Fixes gh-20134