Update generated types to vCenter 7.0U3 (build 18700403)

[zach96guan]

Description

This patch updates the file gen/gen.sh to use vCenter 7.0U3 (build 18700403) as the source for generating types and client bindings for the following packages:

• vim25
• eam
• pbm
• sms (no update)
• vlsm

Closes: #2612

Type of change

Please mark options that are relevant:

• [] Bug fix (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)
• This change requires a documentation update
• Build related change

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. If applicable, please also list any relevant
details for your test configuration.

The following commands were executed locally:

make lint
make install
make test

None of the above checks produced any errors.

Checklist:

• My code follows the CONTRIBUTION guidelines of
  this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

[yuyin002]

Thanks for the change! Would you mind documenting the VC build you used to generate the types?

[zach96guan]

Thanks for the change! Would you mind documenting the VC build you used to generate the types?

TFTR! Add the build number for reference

[dougm]

lgtm , thanks @zach96guan

[HakanSunay]

Looks neat, thanks Zach :)