[BEAM-4787] Ignore generated vendor files in python container build

[angoenka]

Ignore generated files for python container build

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---	---	---	---	---
Java
Python		---		---	---	---	---

[angoenka]

R: @aaltay @tweise

[tweise]

There are a few more vendor files that should me moved out of sight:

	runners/gcp/gcemd/vendor/
	runners/gcp/gcsproxy/vendor/
	sdks/java/container/vendor/
	sdks/python/container/vendor/

I think the existing entry sdks/go/**/vendor/**/* can be augmented to capture the other sdk container builds also?

[angoenka]

Sure, I will add the following to the list. I hope that if we accidentally ignore valid file then we will catch it soon in the build.

sdks/**/vendor/**/*
runners/**/vendor/**/*

[lukecwik]

Thanks for fixing this up.