Release Schedule updated for x.y.1 releases

Hi *,

as discussed by the ESC and announced in the minutes already, the
release plan in the wiki was updated to reflect the decision.

Previously there was a 5 week gap between the .0 and .1 release
followed by a 4 week gap between the .1 and .2 release.

Now the .1 release was moved one week forward, so the gaps are now 4
weeks between .0 and .1, and 5 weeks between .1 and .2

ascii representation of the change (view with fixed-width font):

X.Y.0 5 weeks X.Y.1 4 weeks X.Y.2
X.Y.0 4 weeks X.Y.1 5 weeks X.Y.2

so only the release date of the .1 release changes, the rest of the
schedule remains the same.