Update .gitpod.Dockerfile

Author: tommygonzaleza

.gitpod.Dockerfile

@@ -4,4 +4,4 @@ FROM gitpod/workspace-full:latest
 USER gitpod
 
 RUN npm i jest@24.8.0 -g
-RUN npm i @learnpack/learnpack@2.1.20 -g && learnpack plugins:install @learnpack/html@1.1.1
+RUN npm i @learnpack/learnpack@2.1.20 -g && learnpack plugins:install learnpack-html@0.0.20