Set devel version in master branch

Steps to reproduce:

• check out master
• open CMakeLists.txt

What happened?

INKSCAPE_VERSION_* is 1.0.0-beta2

What should have happened?

Now that we have branched 1.0.x, the version should be different, maybe 1.1.0+devel? Or 1.1.0dev?

Ideally, the devel version string compares 1.1 > devel > 1.0 by package managers.

For example:

>>> from packaging import version
>>> version.parse("1.0") < version.parse("1.1dev")       # OK
True
>>> version.parse("1.1") > version.parse("1.1dev")       # OK
True
>>> version.parse("1.0") < version.parse("1.1-dev")      # OK
True
>>> version.parse("1.1") > version.parse("1.1-dev")      # OK
True
>>> version.parse("1.1alpha") > version.parse("1.1dev")  # OK
True
>>> version.parse("1.1") > version.parse("1.1+devel")    # not OK
False

Unfortunately there seems to be no gold-standard for this, too many conventions exist (e.g. dpkg yields different results in the given example).

Semantic Versioning 2.0.0 allows pre-releases with hyphen: https://semver.org/#spec-item-9