Use StandardCharsets.UTF_8 instead of "UTF-8" string. This removes necessity to throw a checked exception.

And apply replacement:
* "javax.ws.rs.core" => "jakarta.ws.rs.core"

TestImportExportApi: change the file length expectation

This allows clients to implement custom operation more easily.

* Add support for link type between issues

Fixes #847

* Create AbstractIssue

* Add repository submodules api

Fixes #921

* Fix unit test

Fixes #883

Fixes #887

Fixes #936

Co-authored-by: Ипполитов Вадим Дмитриевич <vippolitov@poidem.ru>

Co-authored-by: Jérémie Bresson <dev@jmini.fr>

# Conflicts:
#	pom.xml

Fixes #849

Co-authored-by: Michael Me Jaeger <michael.me.jaeger@deutschebahn.com>

# Conflicts:
#	README.md
#	pom.xml

Replace javax package by jakarta package

Co-authored-by: Michael Fitoussi <16884890+mifitous@users.noreply.github.com>

* Added ReleaseLinks API (#639)

* Deprecate the "external" attribute in Link

* Add tests

* Rename to ReleaseLinksApi and add the getter in GitLabApi

---------

Co-authored-by: Jeremie Bresson <jeremie.bresson@unblu.com>

* Added hook and fetch capabilities

* Fix tests

* Remove superfluous formatting

Fixes #931

* Update to java 11
* Bump version to 6.0.0-SNAPSHOT

Co-authored-by: Gabriel Barbier <gabriel.barbier-ext@nickel.eu>

Co-authored-by: Jeremie Bresson <jeremie.bresson@unblu.com>

* Add getDescendantGroups() methods to GroupApi

* Update javadoc

* Fix typo in method name

* Fix typo in the javadoc

Fixes #889

Add iterationTitle in IssueFilter for filtration issues
by this field

Co-authored-by: Усачев Дмитрий Дмитриевич <92usachevdd@region.cbr.ru>