Use Terminus Build Tools plugin 2.0.0-alpha4 and later. (#121)

* Use Terminus Build Tools plugin 2.0.0-alpha4 and later.

* Comment out BUILD_TOOLS_VERSION so that the version installed in the docker container will be used by default.

Author: greg-1-anderson

.circleci/config.yml

@@ -33,7 +33,7 @@ defaults: &defaults
 
     NOTIFY: 'scripts/github/add-commit-comment {project} {sha} "Created multidev environment [{site}#{env}]({dashboard-url})." {site-url}'
     ADMIN_USERNAME: admin
-    BUILD_TOOLS_VERSION: dev-master
+    # BUILD_TOOLS_VERSION: ^2.0.0-alpha4
     TERM: dumb
 
 version: 2