[main] Update dependencies from dotnet/arcade (#6625)

[main] Update dependencies from dotnet/arcade

eng/Version.Details.xml

@@ -7,9 +7,9 @@
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
-    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="8.0.0-beta.23259.5">
+    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="8.0.0-beta.23261.4">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>08f0d9daf5c5a422b5a22db601ee9fde7068c7ff</Sha>
+      <Sha>06faa97f3e5232df0ddad42caaf28eea39d4ad1a</Sha>
       <SourceBuild RepoName="arcade" ManagedOnly="true" />
     </Dependency>
     <Dependency Name="Microsoft.Net.Compilers.Toolset" Version="4.5.0">

eng/common/cross/x64/sources.list.bionic

@@ -0,0 +1,11 @@
+deb http://archive.ubuntu.com/ubuntu/ bionic main restricted universe
+deb-src http://archive.ubuntu.com/ubuntu/ bionic main restricted universe
+
+deb http://archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe
+deb-src http://archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe
+
+deb http://archive.ubuntu.com/ubuntu/ bionic-backports main restricted
+deb-src http://archive.ubuntu.com/ubuntu/ bionic-backports main restricted
+
+deb http://archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse
+deb-src http://archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse

global.json

@@ -18,6 +18,6 @@
     "rollForward": "patch"
   },
   "msbuild-sdks": {
-    "Microsoft.DotNet.Arcade.Sdk": "8.0.0-beta.23259.5"
+    "Microsoft.DotNet.Arcade.Sdk": "8.0.0-beta.23261.4"
   }
 }