gh-actions: share lfs between operating systems

Author: nschloe

.github/workflows/ci.yml

@@ -39,7 +39,8 @@ jobs:
         id: lfs-cache
         with:
           path: .git/lfs
-          key: ${{ runner.os }}-lfs-${{ hashFiles('.lfs-assets-id') }}-v1
+          # key should be the same for all operating systems
+          key: lfs-${{ hashFiles('.lfs-assets-id') }}-v1
       - name: Git LFS Pull
         run: git lfs pull
 
@@ -79,7 +80,8 @@ jobs:
         id: lfs-cache
         with:
           path: .git/lfs
-          key: ${{ runner.os }}-lfs-${{ hashFiles('.lfs-assets-id') }}-v1
+          # key should be the same for all operating systems
+          key: lfs-${{ hashFiles('.lfs-assets-id') }}-v1
       - name: Git LFS Pull
         run: git lfs pull