Fix buildkite CI

Author: christiangnrd

.buildkite/pipeline.yml

@@ -26,6 +26,7 @@ steps:
 
                   try
                     Pkg.develop([PackageSpec(path=gpuarrays), PackageSpec(path=gpuarrayscore)])
+                    Pkg.add("JLD2") # Test GPUArrays extension
                     TestEnv.activate()
                   catch err
                     @error "Could not install CUDA.jl" exception=(err,catch_backtrace())
@@ -73,6 +74,7 @@ steps:
 
                   try
                     Pkg.develop([PackageSpec(path=gpuarrays), PackageSpec(path=gpuarrayscore)])
+                    Pkg.add("JLD2") # Test GPUArrays extension
                     TestEnv.activate()
                   catch err
                     @error "Could not install oneAPI.jl" exception=(err,catch_backtrace())
@@ -119,6 +121,7 @@ steps:
 
                   try
                     Pkg.develop([PackageSpec(path=gpuarrays), PackageSpec(path=gpuarrayscore)])
+                    Pkg.add("JLD2") # Test GPUArrays extension
                     TestEnv.activate()
                   catch err
                     @error "Could not install Metal.jl" exception=(err,catch_backtrace())