Removed pre-push hook

- we no longer allow pushing to the `main` branch, so this hook is never
  used
- if you tried to push locally, it'd fail because I've since removed
  Lerna
- this commit cleans up the hook

.github/hooks/pre-push

@@ -1,13 +0,0 @@
-#!/bin/bash
-
-[ -n "$CI" ] && exit 0
-
-UPSTREAM=${GHOST_UPSTREAM:-origin}
-GIT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-
-# $1 is the name of the remote to which the push is being done
-if [ "$1" = "$UPSTREAM" ] && [ "$GIT_BRANCH" = "main" ]; then
-    printf "ℹ️ Pushing to \033[0;32m$GIT_BRANCH\033[0m branch requires some checks in advance\n"
-
-    yarn lerna run --include-dependents --since $1/$GIT_BRANCH test:unit
-fi