1.8.0: Finalize release notes (#1905)

* update release notes

* Update release-latest

* Add Development processes section to 1.8 release notes

* Fix warnings from matrixplot

* Update docs/release-notes/1.8.0.rst

Co-authored-by: Giovanni Palla <giov.pll@gmail.com>

Prep 1.7.2 release (#1785)

* Set release date
* Remove unused rubrics from release notes
* enables highly_variable_genes_seurat_v3 to accept pseudocounts (#1679) 
* Add hvg change to release notes

Co-authored-by: Isaac Virshup <ivirshup@gmail.com>
Co-authored-by: giovp <giov.pll@gmail.com>

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

Co-authored-by: Isaac Virshup <ivirshup@gmail.com>

1.7.0

Backport PR #1623: Release note for #1583 and update release date (#1…

1.8.0.dev0

updated test that works with pandas 1.2 (#1584)

1.7.0rc1

Add note about `twine check` to release guide

1.6.1

Make tests run

1.6.0

short version of print_versions and print_header (#1373)

1.5.1

Ignore RandomState references so rtd will build docs

1.5.0

add proper image (#1231)