also update CI

Author: Jutho

.github/workflows/ci.yml

@@ -11,8 +11,7 @@ jobs:
       matrix:
         version:
           - '1.4'
-          - '1.5'
-          - '1.6-nightly'
+          - '1'
         os:
           - ubuntu-latest
           - macOS-latest

.github/workflows/docs.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@latest
         with:
-          version: '1.5'
+          version: '1'
       - name: Install dependencies
         run: julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
       - name: Build and deploy