[org.eclipse.xtext:org.eclipse.xtext] Potentially compromised builds

All Xtext & Xtend versions prior to 2.18.0 were built using HTTP instead of HTTPS file transfer and thus the built artifacts may have been compromised.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-10249
• https://github.com/eclipse/xtext-xtend/issues/759
• https://bugs.eclipse.org/bugs/show_bug.cgi?id=546996
• https://github.com/eclipse/xtext-xtend/commit/169de2cecc50ed9bf81c3cdc496ad8a799bdf17b
• https://github.com/advisories/GHSA-rfj2-4g26-7jw5