Add the missing 2.4.0 tag.

Signed-off-by: Richard Scothern <[email protected]>

library/registry

@@ -5,3 +5,4 @@
 
 2: git://github.com/docker/distribution-library-image@3b41b10642a3c24e2405b8f4cfa1441c54f1c8a2
 2.4: git://github.com/docker/distribution-library-image@3b41b10642a3c24e2405b8f4cfa1441c54f1c8a2
+2.4.0: git://github.com/docker/distribution-library-image@3b41b10642a3c24e2405b8f4cfa1441c54f1c8a2