Fix Ruby-GNOME2 packages version to 2.1.0

The next version of Ruby/ClutterGStreamer on Windows will change API.
Ruby/ClutterGStreamer 2.1.0 on Windows is using Clutter-GStreamer 2.0.8.
However, Clutter-GStreamer's API may be changed from 2.1.0. Probably,
Clutter-GStreamer 2.1.0 may have been released when the next version of
Ruby/ClutterGStreamer is released.
Add 0.1.8 entry
Bump version to 0.1.9

0.1.8 ->
0.1.9
    ^
Merge remote-tracking branch 'origin/master'

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