Test with Julia 1.6 (#68)

Author: tkf

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        julia-version: ['1.5', '1.4', '1.0', 'nightly']
+        julia-version: ['1.6.0-rc1', '1.5', '1.4', '1.0', 'nightly']
       fail-fast: false
     name: Test Julia ${{ matrix.julia-version }}
     steps: