Diasble fail-fast in documentation action

If e.g. the docs build fails on nightly, the docs build on 1.0 (used to 
build the docuemntation that gets deployed) should still run to 
completion.

.github/workflows/Documentation.yml

@@ -12,6 +12,7 @@ jobs:
     name: build on Julia ${{ matrix.julia-version }}
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         julia-version: ['1.0', '1.1', '1.2', '1.3', 'nightly']
     steps: