Update Plugin-Hooks.md

fix typo

Author: zengwei00

docs/Plugin-Hooks.md

@@ -20,7 +20,7 @@ Where `HOOK_NAME` is one of:
 * postclean - This hook is called when the content of the chroot has been deleted. It is called after `umount_root`.  E.g., `lvm_root` use this to delete the LVM volume.
 * postinit - Chroot have been initialized and it is ready for installing SRPM dependencies. E.g., root_cache plugin now packs the chroot and put it in a cache. This action is currently being used by `bind_mount`, `lvm_root`, `mount`, `root_cache` plugins.
 * postshell - This hook is called just after exiting from the shell in `mock shell` command. This action is currently being used by `root_cache` plugin.
-* postupdate - Mock attempts to cache buildroot contents, but tries to automatically update the packages inside the buildroot in subsequent executions (so up2date packages are used during build). This hook is called anytime such udpdate is successul and any package is updated inside the buildroot.  Any plugin taking care of the buildroot caches can then react and update the cache to avoid re-updating in the subsequent mock runs.
+* postupdate - Mock attempts to cache buildroot contents, but tries to automatically update the packages inside the buildroot in subsequent executions (so up2date packages are used during build). This hook is called anytime such udpdate is successful and any package is updated inside the buildroot.  Any plugin taking care of the buildroot caches can then react and update the cache to avoid re-updating in the subsequent mock runs.
 * postumount - This hook is called when everything in chroot finished or has been killed. All inner mounts have been umounted. E.g., tmpfs plugin uses this to umount tmpfs chroot. This action is currently being used by `lvm_root`, `tmpfs` plugins.
 * postyum - This hook is called after any packager manager action is executed. This is e.g., used by the `package_state` plugin to list all available packages. This action is currently being used by `package_state`, `root_cache`, `selinux`, `yum_cache` plugins.
 * prebuild - This hook is called after BuildRequires have been installed, but before RPM builds. This is not called for SRPM rebuilds.