fix os environment variable and update hook version

.github/hooks/pre-commit

@@ -1,15 +1,14 @@
-#!/usr/bin/env sh
-
+#!/bin/sh
 # GITLEAKS_PRECOMMIT_HOOK BEGIN
-precommit_version="v0.0.3"
+precommit_latest_url=$(curl --silent --location --head --output /dev/null --write-out '%{url_effective}' -- https://github.com/GSA/odp-code-repository-commit-rules/releases/latest)
+precommit_version=${precommit_latest_url##*/}
 precommit_url="https://raw.githubusercontent.com/GSA/odp-code-repository-commit-rules/${precommit_version}/gitleaks/precommit.sh"
 precommit_path="$(git rev-parse --show-toplevel)/.git/hooks/precommit.sh"
 
-if [ ! -f "${precommit_path}" ]; then
-	curl --silent -o "${precommit_path}" "${precommit_url}"
-	if [ "$os" = "Linux" ] || [ "$os" = "Darwin" ]; then
-    	chmod +x "${precommit_path}"
-	fi
+curl --silent -o "${precommit_path}" "${precommit_url}"
+os=$(uname -s | cut -d'_' -f 1)
+if [ "$os" = "Linux" ] || [ "$os" = "Darwin" ]; then
+	chmod +x "${precommit_path}"
 fi
 
 "${precommit_path}" "${precommit_version}"