Update workflow to configure Git Safe Directory and copy README to Wiki

Author: JulianPrieber

.github/workflows/copy-readme-to-wiki.yml

@@ -11,6 +11,8 @@ jobs:
         runs-on: ubuntu-latest
         steps:
           - uses: actions/checkout@v2
+          - name: Configure Git Safe Directory
+            run: git config --global --add safe.directory /github/workspace/wiki
           - name: Copy README to Wiki
             run: |
               mkdir -p wiki