Check that all files use LF line endings in CI

.github/workflows/test.yml

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

crlf_test.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+echo "searching for CRLF endings in: ."
+
+BOLD_RED='\033[1;31m'
+BOLD_GREEN='\033[1;32m'
+NC='\033[0m'
+
+ERROR_COUNT=0
+
+if \
+  grep \
+    --recursive \
+    --files-with-matches \
+    --binary \
+    --binary-files=without-match \
+    --max-count=1 \
+    --exclude-dir="\.git" \
+    $'\r' \
+    . \
+  ; then
+  # TODO exit status should be number of files with wrong endings found
+  echo -e "${BOLD_RED}Found at least a file with CRLF endings.${NC}"
+  exit 1
+fi
+
+echo -e "${BOLD_GREEN}No files with CRLF endings found.${NC}"
+exit 0