fix paket.template issue

Author: Eirik Tsarpalis

src/FSharp.Control.AsyncSeq/paket.template

@@ -21,9 +21,9 @@ description
     Asynchronous sequences for F#
 dependencies
   framework: net452
-    FSharp.Core >= LOCKEDVERSION
+    FSharp.Core >= LOCKEDVERSION-Legacy
   framework: netstandard2.0
-	FSharp.Core >= LOCKEDVERSION-Legacy
+	FSharp.Core >= LOCKEDVERSION
 files
     bin/Release/net452/FSharp.Control.AsyncSeq.dll ==> lib/net452
     bin/Release/net452/FSharp.Control.AsyncSeq.pdb ==> lib/net452