chore: Introduce script to update .gitignore

CONTRIBUTING.md

@@ -110,3 +110,9 @@ The Github Workflows manage the release process after the push by doing the foll
 [release]: https://github.com/recyclarr/recyclarr/releases
 [ghcr]: https://github.com/recyclarr/recyclarr/pkgs/container/recyclarr
 [discord]: https://discord.com/invite/Vau8dZ3
+
+## Update `.gitignore`
+
+Execute the `Update-Gitignore.ps1` script using Powershell. The working directory *must* be the root
+of the repo. This will pull the latest relevant `.gitignore` patterns from
+[gitignore.io](https://gitignore.io) and commit them automatically to your current branch.

Update-Gitignore.ps1

@@ -0,0 +1,15 @@
+$ErrorActionPreference = "Stop"
+
+Function gig {
+  param(
+    [Parameter(Mandatory=$true)]
+    [string[]]$list
+  )
+  $params = ($list | ForEach-Object { [uri]::EscapeDataString($_) }) -join ","
+  Invoke-WebRequest -Uri "https://www.toptal.com/developers/gitignore/api/$params" | `
+    Select-Object -ExpandProperty content | `
+    Out-File -FilePath $(Join-Path -path $pwd -ChildPath ".gitignore") -Encoding ascii
+}
+
+gig windows,rider,csharp
+git commit -m 'chore(git): Latest .gitignore from gitignore.io' -- .gitignore