Update version branding to rc1 (#11005)

Author: mmitche

eng/Versions.props

@@ -4,8 +4,8 @@
     <MajorVersion>10</MajorVersion>
     <MinorVersion>0</MinorVersion>
     <PatchVersion>0</PatchVersion>
-    <PreReleaseVersionLabel>preview</PreReleaseVersionLabel>
-    <PreReleaseVersionIteration>7</PreReleaseVersionIteration>
+    <PreReleaseVersionLabel>rc</PreReleaseVersionLabel>
+    <PreReleaseVersionIteration>1</PreReleaseVersionIteration>
     <VersionPrefix>$(MajorVersion).$(MinorVersion).$(PatchVersion)</VersionPrefix>
     <UseVSTestRunner>true</UseVSTestRunner>
     <!--