Add PSScriptAnalyzer action (#59)

Also fix some style problem found by PSScriptAnalyzer.

Pull request: #59

.github/workflows/ci.yml

@@ -3,7 +3,7 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  check:
+  shell:
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
@@ -12,4 +12,15 @@ jobs:
         run: sudo apt-get install -y make shellcheck 
 
       - name: Check
-        run: make clean check
+        run: make clean check
+
+  PowerShell:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Run PSScriptAnalyzer
+        uses: microsoft/psscriptanalyzer-action@v1.1
+        with:
+          path: .\millw.ps1
+          enableExit: true

millw.ps1

@@ -1,5 +1,5 @@
 # This is a wrapper script, that automatically download mill from GitHub release pages
-# You can give the required mill version with -MillVersion parameter
+# You can give the required mill version with --mill-version parameter
 # If no version is given, it falls back to the value of DEFAULT_MILL_VERSION
 #
 # Project page: https://github.com/lefou/millw
@@ -69,10 +69,9 @@ if ($null -eq $MILL_VERSION) {
 
     if ($null -eq $MILL_VERSION) {
         Write-Output 'Retrieving latest mill version ...'
-        
+
         # https://github.com/PowerShell/PowerShell/issues/20964
-        $targetUrl = 
-        try {
+        $targetUrl = try {
             Invoke-WebRequest -Uri "$MILL_REPO_URL/releases/latest" -MaximumRedirection 0
         }
         catch {