Add note regarding Windows VOLUME limitations

Signed-off-by: John Maguire <jmaguire@duosecurity.com>

docs/reference/builder.md

@@ -1222,6 +1222,11 @@ This Dockerfile results in an image that causes `docker run`, to
 create a new mount point at `/myvol` and copy the  `greeting` file
 into the newly created volume.
 
+> **Note**:
+> When using Windows-based containers, the destination of a volume inside the
+> container must be one of: a non-existing or empty directory; or a drive other
+> than C:.
+
 > **Note**:
 > If any build steps change the data within the volume after it has been
 > declared, those changes will be discarded.