Parse odin version date out of HEAD commit if available

misc/get-date.c

@@ -9,5 +9,5 @@
 int main(int arg_count, char const **arg_ptr) {
 	time_t t = time(NULL);
 	struct tm* now = localtime(&t);
-	printf("%04d%02d%02d", now->tm_year + 1900, now->tm_mon + 1, now->tm_mday);
+	printf("%04d-%02d-%02d", now->tm_year + 1900, now->tm_mon + 1, now->tm_mday);
 }