update install to not require sudo/root

[weshayutin]

fixes #30

[weshayutin]

@Joeavaikath @NicholasYancey reviews please

[NicholasYancey]

This change got implemented in this pr #34

[weshayutin]

 make install
Building kubectl-oadp for current platform (linux/amd64)...
✅ Built kubectl-oadp successfully!
Installing kubectl-oadp to /home/whayutin/.local/bin...
cp kubectl-oadp /home/whayutin/.local/bin/
✅ Installed to /home/whayutin/.local/bin

✅ PATH already configured

Test: kubectl oadp --help
whayutin@fedora:~/OPENSHIFT/git/OADP/oadp-cli$ oc oadp
Welcome to the OADP CLI! Use 'kubectl oadp --help' to see available commands.
whayutin@fedora:~/OPENSHIFT/git/OADP/oadp-cli$ oc oadp --help
OADP CLI commands

Usage:
  oadp [flags]
  oadp [command]

Available Commands:
  backup      Work with backups
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  nonadmin    Work with non-admin resources
  restore     Work with restores
  version     Print the velero version and associated image

Flags:
  -h, --help   help for oadp

Use "oadp [command] --help" for more information about a command.
whayutin@fedora:~/OPENSHIFT/git/OADP/oadp-cli$