Dockerfile in fluent-plugin-azure-storage-append-blob-lts-0.5.0 vs Dockerfile in fluent-plugin-azure-storage-append-blob-lts-0.6.0

@@ -1,9 +1,9 @@
-FROM ruby:latest
+FROM ruby:2.7
 
 WORKDIR /plugin
 
-ADD . /plugin
+COPY . /plugin
 
 RUN gem install bundler && \
     gem install fluentd --no-doc && \
     fluent-gem build fluent-plugin-azure-storage-append-blob-lts.gemspec && \
     fluent-gem install fluent-plugin-azure-storage-append-blob-lts-*.gem