install libev on build scripts

+ fix: scanning system dirs on mac

.github/workflows/release.yml

@@ -77,7 +77,7 @@ jobs:
       - name: Activate virtualenv (linux)
         if: matrix.os == 'ubuntu-20.04'
         run: |
-          source .venv/bin/activate && pip install bjoern
+          apt-get install libev-dev && source .venv/bin/activate && pip install bjoern
       - name: Activate virtualenv (windows)
         if: matrix.os == 'windows-2019'
         run: |