python,misc: Fix develop resources URL to v21-0

This was incorrectly kept as `http://dist.gem5.org/dist/develop` in the
v21.0.0 release of gem5. The `dist/develop` directory is used by the
develop branch, not by gem5 releases. This change updates the URL to
point towards the currect v21-0 branch, which will remain stable and
contain resoruces always compatible with the v21-0 release.

Change-Id: I5d9a9497cebffa91f08be253f1637e11e0d5e62c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/44725
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed