fix: make terraform_docs Windows compatible (antonbabenko#129)

Author: matiaszilli

terraform_docs.sh

@@ -52,7 +52,7 @@ terraform_docs_() {
   local -a -r files=("$@")
 
   local hack_terraform_docs
-  hack_terraform_docs=$(terraform version | head -1 | grep -c 0.12) || true
+  hack_terraform_docs=$(terraform version | sed -n 1p | grep -c 0.12) || true
 
   if [[ ! $(command -v terraform-docs) ]]; then
     echo "ERROR: terraform-docs is required by terraform_docs pre-commit hook but is not installed or in the system's PATH."