Enclose shell variables with double quotes

[kyanny]

@gm3dmo

To be shellcheck compliant and to prevent python3 configure.sh from halting with error: argument --ARGUMENT-NAME: expected one argument.

Before

❯ ./dotcom-configure.sh the-power-dotcom.skeleton
the-power-dotcom.skeleton: line 12: syntax error near unexpected token `newline'
the-power-dotcom.skeleton: line 12: `enterprise_name=<your enterprise name>'
usage: configure.py [-h] [-o ORG] [-b BASE_BRANCH] [-d CONFIGURE_GITHUB_APP] [-a APP_ID] [-i INSTALLATION_ID] [-e CLIENT_ID] [--app-client-secret APP_CLIENT_SECRET] [-u ADMIN_USER] [--admin-password ADMIN_PASSWORD] [--mgmt-password MGMT_PASSWORD]
                    [--mgmt-port MGMT_PORT] [-w WEBHOOK_URL] [--x-client-id X_CLIENT_ID] [--x-client-secret X_CLIENT_SECRET] [--number-of-users NUMBER_OF_USERS_TO_CREATE_ON_GHES] [--runner-version RUNNER_VERSION] [--runner-os RUNNER_OS]
                    [--runner-platform RUNNER_PLATFORM] [-c DOTCOM_CONFIG] [-r REPO_NAME] [-n HOSTNAME] [-t TOKEN] [-l LOGLEVEL] [-p PRIMER] [--team-name TEAM_NAME] [--private-pem-file PRIVATE_PEM_FILE] [--number-of-orgs NUMBER_OF_ORGS]
                    [--number-of-repos NUMBER_OF_REPOS] [--number-of-teams NUMBER_OF_TEAMS] [--number-of-branches NUMBER_OF_BRANCHES] [--team-members TEAM_MEMBERS] [--team-admin TEAM_ADMIN] [--default-committer DEFAULT_COMMITTER] [--allow-auto-merge ALLOW_AUTO_MERGE]
                    [--delete-branch-on-merge DELETE_BRANCH_ON_MERGE] [--enterprise-name ENTERPRISE_NAME] [--pr-approver-token PR_APPROVER_TOKEN] [--pr-approver-name PR_APPROVER_NAME] [--preferred_client PREFERRED_CLIENT] [--custom-curl-flags CURL_CUSTOM_FLAGS]
                    [--preferred_browser PREFERRED_BROWSER] [--preferred_browser_mode PREFERRED_BROWSER_MODE] [--chrome-profile CHROME_PROFILE] [--default-repo-visibility DEFAULT_REPO_VISIBILITY] [--github-api-version GITHUB_API_VERSION]
                    [--http-protocol HTTP_PROTOCOL]
configure.py: error: argument --enterprise-name: expected one argument

After

It falls back to the interactive interface. Just like python3 configure.py

❯ ./dotcom-configure.sh the-power-dotcom.skeleton
the-power-dotcom.skeleton: line 12: syntax error near unexpected token `newline'
the-power-dotcom.skeleton: line 12: `enterprise_name=<your enterprise name>'
GitHub hostname = api.github.com
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