Update version numbers for 7.0 Preview 1 (#3610)

Author: paulmedynski

eng/pipelines/libraries/common-variables.yml

@@ -28,17 +28,17 @@ variables:
 
   # Update this after every release. This is used to generate the MDS NuGet package version.
   - name: Major
-    value: '6'
+    value: '7'
   - name: Minor
-    value: '1'
+    value: '0'
   - name: Patch
     value: '0'
 
     # Update this for preview releases.
   - name: Preview
     value: '-preview'
   - name: Revision
-    value: '2'
+    value: '1'
 
   - name: NugetPackageVersion
     value: $(Major).$(Minor).$(Patch)