add --hooks-async and --hooks-before-symlink flags

main.go

@@ -2574,6 +2574,13 @@ OPTIONS
     -?, -h, --help
             Print help text and exit.
 
+	--hooks-async, $GITSYNC_HOOKS_ASYNC
+			Whether to run the --exechook-command asynchronously.
+
+	--hooks-before-symlink, $GITSYNC_HOOKS_BEFORE_SYMLINK
+			Whether to run the --exechook-command before updating the symlink. Use in combination with --hooks-async set
+			to false if you need the hook to finish before the symlink is updated. 
+
     --http-bind <string>, $GITSYNC_HTTP_BIND
             The bind address (including port) for git-sync's HTTP endpoint.
             The '/' URL of this endpoint is suitable for Kubernetes startup and

test_e2e.sh

@@ -3846,7 +3846,8 @@ for t; do
         fi
         remove_containers || true
         run=$((run+1))
-    done    if [[ "$test_ret" != 0 ]]; then
+    done
+    if [[ "$test_ret" != 0 ]]; then
         final_ret=1
         failures+=("$t  (log: ${log}.*)")
     fi