[releng] opened version range for xtext
[releng] opened version range for xtext

Signed-off-by: Jan Koehnlein <23df7e449f68a6059bb601bff6aa0cd72d9882b1@typefox.io>

theia-ide/sprotty,theia-ide/sprotty,theia-ide/sprotty,theia-ide/sprotty