Revert "Allow nightly failure"

This reverts commit 27c49e6.

Author: blegat

.github/workflows/ci.yml

@@ -44,7 +44,6 @@ jobs:
             ${{ runner.os }}-
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
-        continue-on-error: ${{ matrix.version == 'nightly' }}
         with:
           depwarn: error
       - uses: julia-actions/julia-processcoverage@v1