Add Cybozu to options.md (#12324)

Hello.

We want to make our protobuf repository public which contains a custom extension.
Our code is already available at https://github.com/cybozu/protobuf.

Please let us use extension number 1179.

Regards,

Closes #12324

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/12324 from ymmt2005:patch-1 b0a5171211
PiperOrigin-RevId: 519022489

docs/options.md

@@ -456,3 +456,8 @@ with info about your project (name and website) so we can add an entry for you.
 
     *   Website: https://github.com/Neakxs/protocel
     *   Extension: 1177-1178
+
+1.  Cybozu
+
+    *   Website: https://github.com/cybozu/protobuf
+    *   Extension: 1179