Clarify Camunda Modeler Supported Environments

[nikku]

Right now we simply state Linux as part of our supported environments (cf. docs), a statement that does not reflect what is feasible and tested by us.

Generally speaking we are bound to the supported version ranges proclaimed by the Electron project.

This is a tracking issue to clarify the supported environments (Linux + Mac) the modeler is supposed to run at (and tested by us).

Proposal

The following proposal has been discussed with @romansmirnov and is up for merging in the Camunda docs:

Officially supported on the following operating systems:

* Windows 7/10
* Mac OS X 10.11 and later
* Ubuntu LTS (latest)

Reported to work on these operating systems, too:

* Ubuntu 12.04 and later
* Fedora 21
* Debian 8

Tasks

• Update supported environments (feat(supported-environments): clarify Camunda Modeler Linux compat camunda-docs-manual#211)
• Update installation guide (feat(camunda-modeler/installation): clarify required OS camunda-docs-manual#212)
• Communicate in v3.0.0 release notes

Should we communicate this via other means, too?

[nikku]

Will be mentioned in the release blog-post, too.