move to new Dart task model on travis

pkgs/markdown/.travis.yml

diff --git a/pkgs/markdown/.travis.yml b/pkgs/markdown/.travis.yml
index 4d2280d..abf77dd 100644
--- a/pkgs/markdown/.travis.yml
+++ b/pkgs/markdown/.travis.yml
@@ -3,8 +3,14 @@
 dart:
   - stable
   - dev
-  - 1.22.0
+  - 1.22.1
   - 1.21.1
   - 1.20.1
   - 1.19.1
-script: tool/travis.sh
+dart_task:
+  - test: -p vm
+  - dartfmt
+  - dartanalyzer
+cache:
+  directories:
+    - $HOME/.pub-cache

pkgs/markdown/tool/travis.sh

diff --git a/pkgs/markdown/tool/travis.sh b/pkgs/markdown/tool/travis.sh
deleted file mode 100755
index 924c102..0000000
--- a/pkgs/markdown/tool/travis.sh
+++ /dev/null
@@ -1,22 +0,0 @@
-#!/bin/bash
-
-# Fast fail the script on failures.
-set -e
-
-# Analyze sources. Add --fatal-hints, --fatal-warnings, --fatal-lints
-# as you see fit.
-dartanalyzer lib/ test/
-
-# Run tests.
-pub run test
-
-# Assert that code is formatted.
-pub global activate dart_style
-dirty_code=$(pub global run dart_style:format --dry-run lib/ test/ example/ benchmark/)
-if [[ -n "$dirty_code" ]]; then
-  echo Unformatted files:
-  echo "$dirty_code" | sed 's/^/    /'
-  exit 1
-else
-  echo All Dart source files are formatted.
-fi