Prior to this commit, the Undertow compression configuration provided by
Spring Boot would fail and throw an exception for invalid MIME Types
when trying to check them against the list of configured types for
compression.

This commit ensures that invalid MIME Types are ignored and that
compression is disabled for those.

Fixes gh-20955

* pr/20917:
  Polish "Align Kafka's missingTopicsFatal default value"
  Align Kafka's missingTopicsFatal default value

Closes gh-20917

See gh-20917

See gh-20917

* pr/20907:
  Fix typo

Closes gh-20907

See gh-20907

* gh-20799:
  Polish "Update endpoint enablement description to describe availability"
  Update endpoint enablement description to describe availability

Closes gh-20799

See gh-20799

See gh-20799

Closes gh-20889

Closes gh-20678

* pr/20832:
  Update copyright year
  Fix WebappLoader constructor deprecations

Closes gh-20832

See gh-20832

See gh-20832

* pr/20847:
  Polish ConditionMessage#because()

Closes gh-20847

See gh-20847

Since the branch name doesn't always correspond to the milestone name,
eg, master.

See gh-20680

Closes gh-20862

This is done by checking for existing issues only in the milestone
corresponding to the current branch. For issues, the milestone is assigned
at the time of issue creation. For PRs, since the branch is different the
milestone can be derived from that while triaging the issue.

Closes gh-20680

This property is a left-over and was never used in Micrometer so this
commit deprecates its use so that it can be removed in the next feature
release.

Closes gh-20835

This commit fixes the AtlasProperties hierarchy so that it no longer is
a StepRegistryProperties. The AtlasConfig on the Micrometer side of
things does not share the common config hierarchy either and some
properties have different default and lifecycle.

Closes gh-20843

Closes gh-20803

* pr/20756:
  Upgrade to Docker 19.03.8 in CI

Closes gh-20756

See gh-20756

Closes gh-20801

* pr/20793:
  Harmonize issue title for auto-created Docker upgrade issues

Closes gh-20793

See gh-20793

If a PR with the given title exists, we clone the existing PR branch so
that it doesn't get overridden by master.

See gh-20530

See gh-20530

See gh-20530

Closes gh-20752