Prepare release v0.7.6

Prepare 0.7.5 release

Prepare 0.7.4 release

Prepare v0.7.3

Prepare 0.7.2 release

Bug fix release for #224

Release 0.7.0

- enabled semantic highlighting
- bug fixes

Following updates were made:

Sprotty 0.9.0 > 0.12.0

Using Java 11 now instead of Java 1.8.

Following updates were made:
Xtext 2.20 > 2.25
Lsp4j 0.8.1 > 0.10
Sprotty 0.8.0 > 0.9
Elk 0.6.0 > 0.7.0
Mwe2 2.11.1 > 2.12.1
Xerces 2.12.0 > 2.12.2

Release 0.4.2