chore: update the pinned actions with Dependabot and list AlphaFS 2.2.1

- .github/dependabot.yml: weekly updates for the github-actions ecosystem
  only, grouped into one pull request with the commit prefix "ci". The CI
  workflow pins each action by commit SHA with a version comment, which
  Dependabot updates together.
- NTFSSecurity/packages.config listed AlphaFS 2.2.6, but every HintPath and
  the other packages.config files use 2.2.1, the version that ships.
- Tests/Repository.Tests.ps1 (new, 8 tests, no build needed) checks both;
  before the change, 5 of them failed.

No CHANGELOG entry: build and CI metadata only (Decision 7).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: AI Assistant <ai@example.com>

.github/dependabot.yml

@@ -0,0 +1,15 @@
+# Keeps the actions of .github/workflows/ci.yml up to date. The workflow pins
+# each action by commit SHA with the version in a comment; Dependabot updates
+# both and opens one pull request a week for all actions.
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: ci
+    groups:
+      github-actions:
+        patterns:
+          - "*"

NTFSSecurity/packages.config

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="AlphaFS" version="2.2.6" targetFramework="net452" />
+  <package id="AlphaFS" version="2.2.1" targetFramework="net452" />
   <package id="System.Management.Automation.dll" version="10.0.10586.0" targetFramework="net452" />
 </packages>

Tests/Repository.Tests.ps1

@@ -0,0 +1,64 @@
+<#
+    Tests repository files that the build and GitHub use, without a build: every packages.config lists the AlphaFS
+    version that the projects reference and ship, and Dependabot keeps the actions of the CI workflow up to date.
+#>
+[Diagnostics.CodeAnalysis.SuppressMessageAttribute(
+    'PSUseDeclaredVarsMoreThanAssignments', '', Justification = 'Pester shares variables between blocks.'
+)]
+param ()
+
+BeforeDiscovery {
+    $repositoryPath = Join-Path -Path $PSScriptRoot -ChildPath '..'
+    $packageConfigs = foreach ($project in Get-ChildItem -Path $repositoryPath -Filter '*.csproj' -Recurse -Depth 1) {
+        $configPath = Join-Path -Path $project.DirectoryName -ChildPath 'packages.config'
+        if ((Test-Path -LiteralPath $configPath) -and (Select-String -LiteralPath $configPath -Pattern 'id="AlphaFS"' -Quiet)) {
+            @{ Project = $project.Directory.Name; Path = $configPath }
+        }
+    }
+}
+
+Describe 'NuGet packages of the projects' {
+    BeforeAll {
+        $repositoryPath = Join-Path -Path $PSScriptRoot -ChildPath '..'
+        $projects = Get-ChildItem -Path $repositoryPath -Filter '*.csproj' -Recurse -Depth 1
+        $hintPathVersions = @($projects | Select-String -Pattern 'packages\\AlphaFS\.(\d+\.\d+\.\d+)\\' |
+                ForEach-Object -Process { $_.Matches[0].Groups[1].Value } | Sort-Object -Unique)
+    }
+
+    It 'Should reference one AlphaFS version in the HintPaths of all projects' {
+        $hintPathVersions | Should -HaveCount 1
+    }
+
+    It 'Should list the AlphaFS version of the HintPaths in <Project>\packages.config' -ForEach $packageConfigs {
+        $package = ([xml] (Get-Content -LiteralPath $Path -Raw)).packages.package |
+            Where-Object -Property id -EQ -Value 'AlphaFS'
+
+        $package.version | Should -BeExactly $hintPathVersions[0]
+    }
+}
+
+Describe 'Dependabot configuration' {
+    BeforeAll {
+        $configPath = Join-Path -Path $PSScriptRoot -ChildPath '..\.github\dependabot.yml'
+        $lines = if (Test-Path -LiteralPath $configPath) { Get-Content -LiteralPath $configPath } else { @() }
+        $ecosystems = @($lines | Select-String -Pattern '^\s*-\s*package-ecosystem:\s*"?([\w-]+)"?\s*$' |
+                ForEach-Object -Process { $_.Matches[0].Groups[1].Value })
+    }
+
+    It 'Should exist in the .github folder' {
+        $configPath | Should -Exist
+    }
+
+    It 'Should update only the actions of the CI workflow' {
+        $ecosystems | Should -BeExactly @('github-actions')
+    }
+
+    It 'Should check for updates every week' {
+        $lines -match '^\s+interval:\s*"?weekly"?\s*$' | Should -HaveCount 1
+    }
+
+    It 'Should group all updates into one pull request' {
+        $lines -match '^\s+groups:\s*$' | Should -HaveCount 1
+        $lines -match '^\s+-\s*"\*"\s*$' | Should -HaveCount 1
+    }
+}