Update tag to v1.6.2 in readme (#41989)

Author: jishnub

README.md

@@ -101,7 +101,7 @@ Julia. However, most users should use the most recent stable version
 of Julia. You can get this version by changing to the Julia directory
 and running:
 
-    git checkout v1.6.1
+    git checkout v1.6.2
 
 Now run `make` to build the `julia` executable.