Fix pub cache issue in Windows (#39)

Author: mit-mit

example/pubspec.yaml

@@ -1,6 +1,11 @@
 name: example
 publish_to: none
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: ">=2.12.0 <3.0.0"
+
+dependencies:
+  characters:
+    git: https://github.com/dart-lang/characters
+
 dev_dependencies:
   test: any

setup.sh

@@ -85,10 +85,17 @@ fi
 rm "${HOME}/dartsdk.zip"
 
 # Configure pub to use a fixed location.
-echo "PUB_CACHE=${HOME}/.pub-cache" >> $GITHUB_ENV
+if [[ $OS == windows ]]
+then
+  PUBCACHE="${USERPROFILE}\\.pub-cache"
+else
+  PUBCACHE="${HOME}/.pub-cache"
+fi
+echo "PUB_CACHE=${PUBCACHE}" >> $GITHUB_ENV
+echo "Pub cache set to: ${PUBCACHE}"
 
 # Update paths.
-echo "${HOME}/.pub-cache/bin" >> $GITHUB_PATH
+echo "${PUBCACHE}/bin" >> $GITHUB_PATH
 echo "${RUNNER_TOOL_CACHE}/dart-sdk/bin" >> $GITHUB_PATH
 
 # Report success, and print version.