Add release notes URL fallback to canonical URL

update.ps1

@@ -1,8 +1,16 @@
 Import-Module au
 
+$userAgent = "Update checker of Chocolatey Community Package 'xsplit-vcam'"
+
 function global:au_BeforeUpdate ($Package) {
     if ([string]::IsNullOrWhiteSpace($Latest.ReleaseNotes)) {
-        Write-Warning 'release_notes_url is not available - consider requerying the API later!'
+        Write-Warning 'release_notes_url is not available - falling back on redirect from canonical URL'
+
+        $canonicalUri = 'https://xspl.it/vcam/relnotes'
+        $response = Invoke-WebRequest -Uri $canonicalUri -UserAgent $userAgent -MaximumRedirection 0 -SkipHttpErrorCheck -UseBasicParsing -ErrorAction SilentlyContinue
+        $redirectedUri = $response.Headers['Location']
+
+        $Latest.ReleaseNotes = $redirectedUri
     }
 
     #Archive this version for future development, since the vendor does not guarantee perpetual availability
@@ -32,7 +40,6 @@ function global:au_SearchReplace {
 function global:au_GetLatest {
     # Use MSI package, as the copy packaged in EXE package differs slightly and supports less installer properties
     $uri = 'https://www.xsplit.com/api/service/download?page_size=10&application_id=3&active=1&release=0&platform=windows&installer_type=msi'
-    $userAgent = "Update checker of Chocolatey Community Package 'xsplit-vcam'"
 
     $response = Invoke-RestMethod -Uri $uri -UserAgent $userAgent -UseBasicParsing
     $releaseData = $response.data[0]