refactor(typescript): noImplicityAny for topic.ts and subscription.ts

[praveenqlogic]

Fixes #<issue_number_goes_here> (it's a good idea to open an issue first for discussion)

steps
enable noImplicityAny, for subscription.ts and topic.ts file in SRC folder!

• Tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

[JustinBeckwith]

This is looking great! One piece missing though is a.) how you generate the pubsub.d.ts, and b.) making sure it gets copied to the output directory. Please see https://github.com/googleapis/nodejs-logging/blob/master/package.json for an example of how to do both :)

[praveenqlogic]

@JustinBeckwith Hi, i generated a pubsub.d.ts using a below script

"mkdir -p proto && pbjs -t static-module -w commonjs -p node_modules/google-proto-files google/pubsub/v1/pubsub.proto | pbts -o proto/pubsub.d.ts -"

please let me know if i need to commit anything in this regard!

[AVaksman]

@praveenqlogic please add "proto" and "proto:pubsub" to scripts section of package.json as in logging example here

[AVaksman]

• Can google.pubsub.v1.Topic be used instead of object in CreateTopicResponse and for apiResponse type in CreateTopicCallback?

[praveenqlogic]

@JustinBeckwith Hi, let me know if any changes needed on this PR, Hope you like the changes and approve it.

[josecervino]

(To create a reference to issue page) Part of #313

[JustinBeckwith]

We're so close!