Use transparent PNG for logo (#8159)

Author: nicoddemus

README.rst

@@ -1,6 +1,7 @@
-.. image:: https://docs.pytest.org/en/stable/_static/pytest1.png
+.. image:: https://github.com/pytest-dev/pytest/raw/master/doc/en/img/pytest_logo_curves.svg
    :target: https://docs.pytest.org/en/stable/
    :align: center
+   :height: 200
    :alt: pytest
 
 

doc/en/conf.py

@@ -159,7 +159,7 @@
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-html_logo = "img/pytest1.png"
+html_logo = "img/pytest_logo_curves.svg"
 
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32