Fix publish script. (#2086)

tool/publish.sh

diff --git a/tool/publish.sh b/tool/publish.sh
index 8eaf369..0a5e6a1 100755
--- a/tool/publish.sh
+++ b/tool/publish.sh
@@ -8,7 +8,7 @@
 echo "Editing .gitignore to comment out build directory"
 
 pushd packages/devtools_app
-pub get
+flutter pub get
 popd
 
 tool/build_release.sh