ci: run with latest stable version

Author: inkydragon

.buildkite/runtests.yml

@@ -13,7 +13,7 @@ steps:
           gid: 1000
       # Julia installation inside the sandbox
       - JuliaCI/julia#v1:
-          version: "nightly"
+          version: "1"
           arch: "i686"
     command: |
       julia --color=yes --project=.ci -e 'using Pkg; Pkg.instantiate()'
@@ -38,7 +38,7 @@ steps:
           gid: 1000
       # Julia installation inside the sandbox
       - JuliaCI/julia#v1:
-          version: "nightly"
+          version: "1"
     command: |
       julia --color=yes --project=.ci --code-coverage=@ -e 'using Pkg; Pkg.instantiate()'
       julia --color=yes --project=.ci --code-coverage=@ .ci/create_sysimage_and_run_tests.jl
@@ -51,7 +51,7 @@ steps:
   - label: ":macos: macos-aarch64"
     plugins:
       - JuliaCI/julia#v1:
-          version: "nightly"
+          version: "1"
       - JuliaCI/julia-coverage#v1:
           codecov: true
     command: |
@@ -65,7 +65,7 @@ steps:
   - label: ":windows: windows-x86_64"
     plugins:
       - JuliaCI/julia#v1:
-          version: "nightly"
+          version: "1"
       - JuliaCI/julia-coverage#v1:
           codecov: true
     command: |