Fix recursive git archive reference

Broken link for "recursive git archive" example

README.md

@@ -138,7 +138,7 @@ However, in order to build from a git clone, you must update the
 submodules.  If you're packaging OSTree and want a tarball, I
 recommend using a "recursive git archive" script.  There are several
 available online;
-[this code](https://github.com/ostreedev/ostree/blob/main/packaging/Makefile.dist-packaging#L11)
+[this code](https://github.com/ostreedev/ostree/blob/main/ci/Makefile.dist-packaging#L18)
 in OSTree is an example.
 
 Once you have a git clone or recursive archive, building is the