fix license type in README

Forgot to include with #40

Author: jerdog

README.md

@@ -256,7 +256,7 @@ Community-sourced tools for the DevRel industry. Brought to you by [The DevRel C
 * [CMX Summit](https://cmxhub.com/summit/)
 
 # LICENSE
-<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>.
+<a rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://mirrors.creativecommons.org/presskit/buttons/88x31/png/by-sa.png" /></a><br />This work is licensed under a <a rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution Share Alike 4.0 International License</a>.
 
 # Resource Templates