add typing to DepsTask.run

[MichelleArk]

resolves #6191

Description

fire_event(DepsNotifyUpdatesAvailable(packages=packages_to_upgrade)) was previously passing packages as a list of strings which could not be serialized to the new ListOfStrings protobuf type during logging.

dbt --log-format json deps logged the following error event when installing a package that has an update available:

{"exc": "type DepsNotifyUpdatesAvailable is not serializable. 'str' object has no attribute 'to_dict'", "info": {"code": "Z002", "extra": {}, "invocation_id": "1e59a3df-3a23-42d9-aa45-d2246092cd70", "level": "error", "msg": "Encountered an error:\ntype DepsNotifyUpdatesAvailable is not serializable. 'str' object has no attribute 'to_dict'", "name": "MainEncounteredError", "pid": 51212, "thread": "MainThread", "ts": "2022-11-02T00:02:17.987107Z"}}

Ideally mypy would have caught this issue but DepsTask.run was not scanned by mypy because the method signature did not have type annotations. After adding type annotations to the DepsTask.run, mypy was able to detect the issue (as well as a few others which are also addressed in this change):

❯ mypy core/dbt/task/deps.py
core/dbt/task/deps.py:90: error: Argument "packages" to "DepsNotifyUpdatesAvailable" has incompatible type "List[str]"; expected "ListOfStrings"
Found 1 error in 1 file (checked 1 source file)

Checklist

• I have read the contributing guide and understand what's expected of me
• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have opened an issue to add/update docs, or docs changes are not required/relevant for this PR
• I have run changie new to create a changelog entry

[github-actions]

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[iknox-fa]

LGTM