License code under Apache v2 and documentation under the CC BY 4.0.

Following guidance from the CNCF's IP policy https://github.com/cncf/foundation/blob/main/charter.md#11-ip-policy

Signed-off-by: Matt Ray <github@mattray.dev>

docs/README.md

@@ -1 +1,3 @@
-The docs are available at <https://www.opencost.io/docs/> and the source is at <https://github.com/opencost/opencost-website/>
+The docs are available at <https://www.opencost.io/docs/> with additional source at <https://github.com/opencost/opencost-website/>.
+
+All documentation in this repository is made available by the CNCF under the [Creative Commons Attribution 4.0 International License](https://creativecommons.org/licenses/by/4.0/).