manually link openbabel header files

Author: janosh

.github/workflows/test.yml

@@ -8,8 +8,7 @@ on:
 
 jobs:
   test:
-    # don't run on forks
-    if: github.repository_owner == 'hackingmaterials'
+    if: github.repository_owner == 'hackingmaterials' # don't run on forks
     runs-on: ubuntu-latest
 
     steps:
@@ -23,18 +22,22 @@ jobs:
 
       - name: Install OpenBabel
         run: |
-          sudo apt-get install openbabel python3-openbabel
+          sudo apt-get install libopenbabel-dev
+          # https://github.com/openbabel/openbabel/issues/2408#issuecomment-1014466193
+          sudo ln -s /usr/include/openbabel3 /usr/local/include/openbabel3
 
       - name: Cache pip
         uses: actions/cache@v2
         with:
           path: ~/.cache/pip
-          key: ${{ runner.os }}-pip-${{ hashFiles('requirements-ci.txt') }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('requirements-ci.txt', 'setup.py') }}
           restore-keys: |
             ${{ runner.os }}-pip-
 
       - name: Install dependencies
         run: |
+          which pip
+          pip --version
           pip install -r requirements-ci.txt
           pip install .[complete]