V4 - Use new .NET CDN URLs and update to latest install scripts (#566)

* Use new .NET CDN URL

* Update to latest install-dotnet scripts

* Use signed version of new `install-dotnet.ps1`

* Add fallback to old CDN URL

Author: heavymachinery

dist/setup/index.js

@@ -93806,7 +93806,13 @@ class DotnetVersionResolver {
                 allowRetries: true,
                 maxRetries: 3
             });
-            const response = yield httpClient.getJson(DotnetVersionResolver.DotnetCoreIndexUrl);
+            let response;
+            try {
+                response = yield httpClient.getJson(DotnetVersionResolver.DotnetCoreIndexUrl);
+            }
+            catch (error) {
+                response = yield httpClient.getJson(DotnetVersionResolver.DotnetCoreIndexFallbackUrl);
+            }
             const result = response.result || {};
             const releasesInfo = result['releases-index'];
             const releaseInfo = releasesInfo.find(info => {
@@ -93821,7 +93827,8 @@ class DotnetVersionResolver {
     }
 }
 exports.DotnetVersionResolver = DotnetVersionResolver;
-DotnetVersionResolver.DotnetCoreIndexUrl = 'https://dotnetcli.azureedge.net/dotnet/release-metadata/releases-index.json';
+DotnetVersionResolver.DotnetCoreIndexUrl = 'https://builds.dotnet.microsoft.com/dotnet/release-metadata/releases-index.json';
+DotnetVersionResolver.DotnetCoreIndexFallbackUrl = 'https://dotnetcli.azureedge.net/dotnet/release-metadata/releases-index.json';
 class DotnetInstallScript {
     constructor() {
         this.scriptName = utils_1.IS_WINDOWS ? 'install-dotnet.ps1' : 'install-dotnet.sh';