update Bullseye from 2.4.0-alpha.1 to 2.4.0-beta.1 (#3949)

Author: adamralph

build/scripts/scripts.fsproj

@@ -68,7 +68,7 @@
     <FscToolExe>fsharpc</FscToolExe>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Bullseye" Version="2.4.0-alpha.1" />
+    <PackageReference Include="Bullseye" Version="2.4.0-beta.1" />
     <PackageReference Include="Elastic.Managed" Version="0.1.0-ci20190627T121416" />
     <PackageReference Include="Fake.Core.Environment" Version="5.15.0" />
     <PackageReference Include="Fake.Core.SemVer" Version="5.15.0" />