Change the recommended example build path

Replace the CI build path with the "example" build path. The CI build is
designed to test key parts of the workflow for our own development
purposes, but it is not the ideal workflow for new users.

README.md

@@ -36,7 +36,7 @@ for Nextstrain's suite of software tools.
 Then run the example build via:
 
 ```
-nextstrain build .  --configfile profiles/ci/builds.yaml
+nextstrain build .  --configfile profiles/example/builds.yaml
 ```
 
 When the build has finished running, view the output Auspice trees via: