Remove script for creating master sync PR (#10791)

The script responsible for creating the "Sync `master` with `develop`"
PR has been removed. We will soon be eliminating the need for a
`master` branch altogether, so we don't need this anymore. Also, this
script hasn't been running correctly in a long time. We've been
creating this PR manually.

.circleci/config.yml

@@ -470,9 +470,6 @@ jobs:
           name: Create GitHub release
           command: |
             .circleci/scripts/release-create-gh-release.sh
-      - run:
-          name: Create GitHub Pull Request to sync master with develop
-          command: .circleci/scripts/release-create-master-pr.sh
 
   job-publish-storybook:
     executor: node-browsers

.circleci/scripts/release-create-master-pr.sh

@@ -1,52 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-set -u
-set -o pipefail
-
-if [[ "${CI:-}" != 'true' ]]
-then
-    printf '%s\n' 'CI environment variable must be set to true'
-    exit 1
-fi
-
-if [[ "${CIRCLECI:-}" != 'true' ]]
-then
-    printf '%s\n' 'CIRCLECI environment variable must be set to true'
-    exit 1
-fi
-
-if [[ -z "${GITHUB_TOKEN:-}" ]]
-then
-    printf '%s\n' 'GITHUB_TOKEN environment variable must be set'
-    exit 1
-fi
-
-function install_github_cli ()
-{
-    printf '%s\n' 'Installing hub CLI'
-    pushd "$(mktemp -d)"
-        curl -sSL 'https://github.com/github/hub/releases/download/v2.11.2/hub-linux-amd64-2.11.2.tgz' | tar xz
-        PATH="$PATH:$PWD/hub-linux-amd64-2.11.2/bin"
-    popd
-}
-
-base_branch='develop'
-
-if [[ -n "${CI_PULL_REQUEST:-}" ]]
-then
-    printf '%s\n' 'CI_PULL_REQUEST is set, pull request already exists for this build'
-    exit 0
-fi
-
-install_github_cli
-
-printf '%s\n' "Creating a Pull Request to sync 'master' with 'develop'"
-
-if ! hub pull-request \
-    --message "Master => develop" --message 'Merge latest release back into develop' \
-    --base "$CIRCLE_PROJECT_USERNAME:$base_branch" \
-    --head "$CIRCLE_PROJECT_USERNAME:$CIRCLE_BRANCH";
-then
-    printf '%s\n' 'Pull Request already exists'
-fi