installer script fails when tput is unavailable

[abernix]

Description

When running the installer in a more minimalistic shell/environment (e.g., Alpine), the installer fails because of an absence of the tput command. The tput command is leveraged to power ANSI colors in the installer output.

Could we consider making tput an optional dependency of the installer script where — in its absence — the use of colored terminal output would degrade gracefully?

The existing Spaceport installer guarded against the absence of this tput command: https://github.com/apollographql/spaceport/blob/44d8921e6e4d098fdc90dfbded7b959c60d8cb0a/public/install.sh#L1-L24

Steps to reproduce

This requires Docker, but this should reproduce:

docker run --rm -t -i alpine:latest \
  sh -c 'apk add curl && curl -sSL https://raw.githubusercontent.com/apollographql/rover/v0.0.4/installers/binstall/scripts/nix/install.sh | sh'

Expected result

Rover installation!

Actual result

/ # curl -sSL https://raw.githubusercontent.com/apollographql/rover/v0.0.4/installers/binstall/scripts/nix/install.sh | sh
sh: tput: not found
sh: tput: not found
sh: tput: not found
sh: tput: not found
ERROR: need 'tput' (command not found)
/ #

Environment

Run rover info and paste the results here Can't install!

• Operating system and version: Alpine Linux

• Shell (bash/zsh/powershell):

  / # cat /etc/os-release
  NAME="Alpine Linux"
  ID=alpine
  VERSION_ID=3.12.0
  PRETTY_NAME="Alpine Linux v3.12"
  HOME_URL="https://alpinelinux.org/"
  BUG_REPORT_URL="https://bugs.alpinelinux.org/"
  / #
  

• Version of Rover (rover --help): In theory, 0.0.4

• Installation method: curl