Upgrade to Tycho 2.7.5

We should upgrade as then we can remove org.sonatype.tycho.m2 dependency:

Eclipse M2E lifecycle-mapping metadata embedded

All Tycho plugins are now shipped with embedded M2E lifecycle-mapping-metadata files. Therefore M2E now knows by default how to handle them and it is not necessary anymore to install any connector (usually org.sonatype.tycho.m2e was used) for them.

That dependecy gives problem when upgrading to a new Eclipse release: see here.

Also, there is a bug in Tycho 3.0 that prevents upgrading to it. Tycho 4.0 has not been released yet.