Merge pull request #16 from jonasbb/ci

Run shellcheck during CI

Author: jonasbb

.github/workflows/ci.yml

@@ -0,0 +1,13 @@
+name: "Check Script Files"
+on:
+  pull_request:
+  push:
+
+jobs:
+  check_script_files:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: "Shellcheck"
+        run: shellcheck --check-sourced *.sh