Upgrade to Eclipse 2022-06

I propose we skip Eclipse 2021-09 and go directly to Eclipse 2021-12 2022-06.

While Eclipse 2021-12 also supports Java 17, the next Java LTS release, this issue is not about upgrading to a newer Java version. For that, see #259 (closed). (Originally #259 (closed) was part of this issue, but it has now been split into a separate issue to allow addressing them separately.)