Update pubs.opengroup.org links for POSIX 2024 (and https).

Change-Id: I5ac55398561c3da5b7915a479dbbb709ae98c758
diff --git a/libc/bionic/spawn.cpp b/libc/bionic/spawn.cpp
index 8cee8b8..d97057f 100644
--- a/libc/bionic/spawn.cpp
+++ b/libc/bionic/spawn.cpp
@@ -187,7 +187,7 @@
                        char* const env[],
                        int exec_fn(const char* path, char* const argv[], char* const env[])) {
   // See https://man7.org/linux/man-pages/man3/posix_spawn.3.html
-  // and http://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_spawn.html
+  // and https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/posix_spawn.html
 
   ScopedSignalBlocker ssb;