ISSUE #25 Adds VPC ID in client VPN endpoint argument

[adeelamin15]

Solves the issue reported https://github.com/DNXLabs/terraform-aws-client-vpn/issues/25

Types of changes

• [x] Bugfix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation Update (if none of the other choices apply)

Checklist

• [x] I have read the CONTRIBUTING.md doc.
• [x] I have added necessary documentation (if appropriate).
• [x] Any dependent changes have been merged and published in downstream modules.

Further comments

This fix is necessary to get main upstream repo working. As of now the present upstream branch is broken.

[adeelamin15]

@mcosta1105 Please review and merge. It is breaking main upstream branch as reported in bug.

[adeelamin15]

@adenot @lzrocha @RaphaelMacedonio Please review this PR . Without this original latest release is broken. Issue is described in the PR description.

[mcosta1105]

Thanks for creating this PR @adeelamin15