Remove OpenCollective from README

Author: maennchen

README.md

@@ -1,6 +1,5 @@
 # Quantum
 
-[![Financial Contributors on Open Collective](https://opencollective.com/quantum/all/badge.svg?label=financial+contributors)](https://opencollective.com/quantum)
 [![.github/workflows/branch_main.yml](https://github.com/quantum-elixir/quantum-core/actions/workflows/branch_main.yml/badge.svg)](https://github.com/quantum-elixir/quantum-core/actions/workflows/branch_main.yml)
 [![Coverage Status](https://coveralls.io/repos/quantum-elixir/quantum-core/badge.svg?branch=main)](https://coveralls.io/r/quantum-elixir/quantum-core?branch=main)
 [![Module Version](https://img.shields.io/hexpm/v/quantum.svg)](https://hex.pm/packages/quantum)
@@ -107,35 +106,6 @@ This project uses the [Collective Code Construction Contract (C4)](http://rfc.ze
 6. Pull requests SHALL be named as "Solution: _description of your solution_"
 7. Your pull request is merged and you are added to the [list of contributors](https://github.com/quantum-elixir/quantum-core/graphs/contributors)
 
-### Code Contributors
-
-This project exists thanks to all the people who contribute.
-
-[![Contributors](https://opencollective.com/quantum/contributors.svg?width=890&button=false)](https://github.com/quantum-elixir/quantum-core/graphs/contributors)
-
-### Financial Contributors
-
-Become a financial contributor and help us sustain our community. [[Contribute](https://opencollective.com/quantum/contribute)]
-
-#### Individuals
-
-[![Individuals](https://opencollective.com/quantum/individuals.svg?width=890)](https://opencollective.com/quantum)
-
-#### Organizations
-
-Support this project with your organization. Your logo will show up here with a link to your website. [[Contribute](https://opencollective.com/quantum/contribute)]
-
-[![Organization0](https://opencollective.com/quantum/organization/0/avatar.svg)](https://opencollective.com/quantum/organization/0/website)
-[![Organization1](https://opencollective.com/quantum/organization/1/avatar.svg)](https://opencollective.com/quantum/organization/1/website)
-[![Organization2](https://opencollective.com/quantum/organization/2/avatar.svg)](https://opencollective.com/quantum/organization/2/website)
-[![Organization3](https://opencollective.com/quantum/organization/3/avatar.svg)](https://opencollective.com/quantum/organization/3/website)
-[![Organization4](https://opencollective.com/quantum/organization/4/avatar.svg)](https://opencollective.com/quantum/organization/4/website)
-[![Organization5](https://opencollective.com/quantum/organization/5/avatar.svg)](https://opencollective.com/quantum/organization/5/website)
-[![Organization6](https://opencollective.com/quantum/organization/6/avatar.svg)](https://opencollective.com/quantum/organization/6/website)
-[![Organization7](https://opencollective.com/quantum/organization/7/avatar.svg)](https://opencollective.com/quantum/organization/7/website)
-[![Organization8](https://opencollective.com/quantum/organization/8/avatar.svg)](https://opencollective.com/quantum/organization/8/website)
-[![Organization9](https://opencollective.com/quantum/organization/9/avatar.svg)](https://opencollective.com/quantum/organization/9/website)
-
 ## Copyright and License
 
 Copyright (c) 2015 Constantin Rack