Update buildkite config

Author: pxl-th

.buildkite/pipeline.yml

@@ -76,7 +76,6 @@ steps:
         push!(conf[\"targets\"][\"test\"], \"AMDGPU\")
         open(io -> TOML.print(io, conf), \"Project.toml\", \"w\")
         """
-      - julia --project -e 'using Pkg; Pkg.update()'
     timeout_in_minutes: 30
     env:
       JULIA_AMDGPU_CORE_MUST_LOAD: "1"