fix julia version for benchmark

Author: tmigot

.github/workflows/Benchmark.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@latest
         with:
-          version: 1
+          version: lts
       - uses: julia-actions/julia-buildpkg@latest
       - name: Install dependencies
         run: julia -e 'using Pkg; pkg"add PkgBenchmark BenchmarkCI"'