restore logo for README.md

Docker-DCO-1.1-Signed-off-by: Alex Hirsch <ax.warhawk@gmail.com> (github: W4RH4WK)

README.md

@@ -18,7 +18,7 @@ It benefits directly from the experience accumulated over several years
 of large-scale operation and support of hundreds of thousands of
 applications and databases.
 
-![Docker L](docs/theme/mkdocs/img/logo_compressed.png "Docker")
+![Docker L](docs/theme/mkdocs/images/docker-logo-compressed.png "Docker")
 
 ## Better than VMs