Add .swiftpm to gitignore to stop schemes from polluting packages that depend on NetworkService

[roanutil]

• Add .swiftpm to gitignore to stop schemes from polluting packages that depend on NetworkService
• Run swiftformat
• Update ci.yml to use newer codecov flow
• Add codecov badge to README
• Remove unnecessary use of try!. Resolves issue Unnecessary try! in MockOutput conformances #1.
• Add missing assertion descriptions in tests. Resolves swiftlint warnings.

feature/stop-schemes-from-polluting-dependents

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (main@036aaf9). Click here to learn what that means.
The diff coverage is n/a.

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  Hits            ?     1154           
  Misses          ?      380           
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