git: _really_ allow running in bare repositories

When I authored 176113f (git: allow operating on bare repositories,
2023-10-01), I obviously tested only with absolute `workDir` values.
Let's make it work with relative ones, too, by avoiding to override the
working directory _in addition_ to specifying `--git-dir=<path>`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

lib/git.ts

@@ -37,10 +37,12 @@ function trimTrailingNewline(str: string): string {
  * @throws {Error} if the command fails
  */
 export function git(args: string[], options?: IGitOptions): Promise<string> {
+    let workDir = (options && options.workDir) || ".";
     // allow the command to run in a bare repository
-    if (options?.workDir?.endsWith(".git")) args = [`--git-dir=${options.workDir}`, ...args];
-
-    const workDir = (options && options.workDir) || ".";
+    if (options?.workDir?.endsWith(".git")) {
+        args = [`--git-dir=${options.workDir}`, ...args];
+        workDir = ".";
+    }
     if (options && options.trace) {
         process.stderr.write(`Called 'git ${args.join(" ")}' in '${workDir}':\n${new Error().stack}\n`);
     }