Test on Julia 1.8 instead of 1.7 (#62)

Author: rikhuijzer

.github/workflows/CI.yml

@@ -22,7 +22,7 @@ jobs:
       matrix:
         version:
           - '1.6'
-          - '1.7'
+          - '1.8'
         os:
           - ubuntu-latest
           - windows-latest
@@ -50,7 +50,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
         with:
-          version: '1.7'
+          version: '1.8'
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
       - run: julia --project=docs -e '