Switch back GitHub Actions workflow to use current Tycho version

[HeikoKlare]

The Tycho version used in GitHub Actions workflow has been temporarily reverted to 4.0.8. This change switched back the Tycho version defined in the Tycho build itself.

⚠️ This PR is supposed to be merged once the issue discussed in eclipse-platform/eclipse.platform.releng.aggregator#2360 and reproduced via eclipse-tycho/tycho#4293 has been resolved or once we want to have SWT use latest Tycho again to further investigate the failures.

[github-actions]

Test Results

  281 files   -   202    281 suites   - 202   5m 50s ⏱️ - 2m 59s
4 095 tests ±    0  4 085 ✅ ±    0   7 💤 ± 0  3 ❌ ±0 
8 121 runs   - 8 052  8 062 ✅  - 8 018  56 💤  - 34  3 ❌ ±0 

For more details on these failures, see this check.

Results for commit 6697e22. ± Comparison against base commit df66a8b.

♻️ This comment has been updated with latest results.

[HeikoKlare]

I've experimentally changed this PR to use Tycho 4.0.10-SNAPSHOT, in order to validate that the reason for temporarily switching back to Tycho 4.0.8 (failures during testCompile on Linux/MacOS) has been resolved.

The builds now successfully pass that compilation step (@laeubi fyi).
They still fail, but for different, unrelated reasons:

• Linux: Multiple tests failing in Test_org_eclipse_swt_browser_Browser #1564
• macOS: Remove obsolete API filter for GCData and Display on MacOS #1478

I guess there are no plans for releasing Tycho 4.0.10 soon? So would it make sense to upgrade the whole platform to use 4.0.10-SNAPSHOT, or should we maybe at least apply it to the GH actions builds of SWT?

[sratz]

I guess there are no plans for releasing Tycho 4.0.10 soon?

There are: eclipse-tycho/tycho#2455 (comment)