Use java 11 toolchain and increase minimum java version to 11

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❌ Changes break the MontiVerse

Project	Status
artifacts	❌

details

Project	Status
montiarc	✅
umlp	✅
sd	✅
montifun	✅
fd	✅
automaton	✅
sc	✅
guidsl	✅
artifacts	❌
ocl	✅
od	✅
ucd	✅
langexperiments	✅
json	✅
xml	✅
cd2gui	✅
mlc	✅
cd4analysis	✅
monticore_basic	✅
class2mc	✅

The MontiVerse is a collection of (internal and public) language projects.