feat(microservices): support ncc when using grpc

[zanminkian]

A well-performed nestjs standard project, which transport is Transport.GRPC and protoLoader is @grpc/proto-loader, is not compatible with npm package @vercel/ncc. The reason is - ncc compiling js file use static analysation. Therefore, require(someVar) is not supported by ncc, but require("some-string") works well.

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

• Step1: run nest build in a standard nestjs project that its transport is Transport.GRPC and its protoLoader is @grpc/proto-loader
• Step2: run npm i -g @vercel/ncc && ncc build dist/main.js -m -o out
• Step3: run node out/index.js to bootstrap, but fail

What is the new behavior?

• Step1: run nest build in a standard nestjs project that its transport is Transport.GRPC and its protoLoader is @grpc/proto-loader
• Step2: run npm i -g @vercel/ncc && ncc build dist/main.js -m -o out
• Step3: run node out/index.js to bootstrap, success.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

Left 2 minor comments, otherwise it looks great

[coveralls]

Pull Request Test Coverage Report for Build bcea77f5-5d40-44f5-b790-7c93618f653d

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.002%) to 94.082%

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Totals
Change from base Build 8b22cdab-da56-48e2-8ec8-1138233399c3:	0.002%
Covered Lines:	5660
Relevant Lines:	6016

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💛 - Coveralls

[kamilmysliwiec]

LGTM