fix: make trimTrailingDotGit null safe

Author: kriswest

src/db/helper.ts

@@ -6,7 +6,7 @@ export const toClass = function (obj: any, proto: any) {
 
 export const trimTrailingDotGit = (str: string): string => {
   const target = '.git';
-  if (str.endsWith(target)) {
+  if (str && str.endsWith(target)) {
     // extract string from 0 to the end minus the length of target
     return str.slice(0, -target.length);
   }