Check that all files use LF line endings in CI

.github/workflows/test.yml

@@ -41,3 +41,10 @@ jobs:
       run: |
         go version
         go test ./...
+  code-checks:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Test that only LF line endings are used
+      run: bash crlf_test.sh

crlf_test.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+if \
+	grep \
+		--recursive \
+		--files-with-matches \
+		--binary \
+		--binary-files=without-match \
+		--max-count=1 \
+		--exclude-dir="\.git" \
+		$'\r' \
+		. \
+	; then
+	# TODO exit status should be number of files with wrong endings found
+	echo -e "Found at least a file with CRLF endings."
+	exit 1
+fi
+
+echo -e "No files with CRLF endings found."
+exit 0