chore: add balsamiq logo and update readme

.eslintignore

@@ -12,3 +12,5 @@ Dockerfile
 *.rpi
 *.html
 *.scss
+*.png
+*.jpg

README.md

@@ -164,16 +164,15 @@ Verdaccio aims to support all features of a standard npm client that make sense
 - npm audit - **supported**
 
 
-## Sponsors
+## Special Thanks
 
-#### Open Source License
-
-Thanks to the following sponsors to help to achieve our goals providing us free open source licenses.
+Thanks to the following companies to help us to achieve our goals providing free open source licenses.
 
 [![jetbrain](assets/sponsor/jetbrains/logo.png)](https://www.jetbrains.com/)
 [![crowdin](assets/sponsor/crowdin/logo.png)](https://crowdin.com/)
+[![balsamiq](assets/sponsor/balsamiq/logo.jpg)](https://balsamiq.com/)
 
-#### Open Collective
+### Sponsors
 
 Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [[Become a sponsor](https://opencollective.com/verdaccio#sponsor)]