Backport PR scverse#1683: Update release notes for 1.7.1 (scverse#1686)

Co-authored-by: Isaac Virshup <[email protected]>

Backport PR scverse#1623: Release note for scverse#1583 and update re…

…lease date (scverse#1624)

Co-authored-by: Isaac Virshup <[email protected]>

updated test that works with pandas 1.2 (scverse#1584)

Add note about `twine check` to release guide

Make tests run

short version of print_versions and print_header (scverse#1373)

Ignore RandomState references so rtd will build docs

add proper image (scverse#1231)

add proper image (scverse#1231)

Docs 1.4.6 (scverse#1112)

* reorganized landing page and release notes

* version 1.4.6

* added reference to sam docstring