[espresso] Minor cleanup

[stuartmorgan]

• Stop using the legacy analysis options
• Switch from "homepage" to "repository" in pubspec.yaml (and fix the link)
• Add a specific issue query as "issue_tracker" in pubspec.yaml

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide and the C++, Objective-C, Java style guides. (Note that unlike the flutter/flutter repo, the flutter/plugins repo does use dart format. See plugin_tool format)
• I signed the CLA.
• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• I listed at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy.
• I updated CHANGELOG.md to add a description of the change.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test exempt.
• All existing and new tests are passing.

[stuartmorgan]

This updates the version so that I can publish it as a test to make sure this issue_tracker entry will work as expected, before rolling that change out across the repository.

[blasten]

TIL

[blasten]

LGTM