bump nuspec to 2.9.0

Author: gshackles

nuspec/Cirrious.FluentLayout.nuspec

@@ -2,14 +2,14 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
     <metadata>
         <id>Cirrious.FluentLayout</id>
-        <version>2.8.0</version>
+        <version>2.9.0</version>
         <authors>slodge</authors>
         <owners>gshackles,slodge</owners>
         <licenseUrl>https://github.com/slodge/Cirrious.FluentLayout/blob/master/LICENSE</licenseUrl>
         <projectUrl>https://github.com/slodge/Cirrious.FluentLayout</projectUrl>
         <requireLicenseAcceptance>false</requireLicenseAcceptance>
         <description>Easy API for using AutoLayout in iOS</description>
-        <releaseNotes>Added support for safe area guides</releaseNotes>
+        <releaseNotes>Added support for aligning based on the center of another view</releaseNotes>
         <copyright>Copyright 2018</copyright>
         <tags>iOS AutoLayout</tags>
     </metadata>