[google_maps_flutter_web] Downgrade mockito in example app.

[ditman]

Mockito 5 + integration_test from SDK in stable are not compatible:

google_maps_flutter_web/example$ flutter analyze

Because every version of integration_test from sdk depends on crypto 2.1.5 and analyzer >=1.0.0 depends on crypto ^3.0.0, integration_test from sdk is incompatible with analyzer >=1.0.0.
And because mockito 5.0.0 depends on analyzer ^1.0.0 and no versions of mockito match >5.0.0 <6.0.0, integration_test from sdk is incompatible with mockito ^5.0.0.
So, because google_maps_flutter_web_integration_tests depends on both mockito ^5.0.0 and integration_test any from sdk, version solving failed.

Running "flutter pub get" in example...                                 

pub get failed (1; So, because google_maps_flutter_web_integration_tests depends on both mockito ^5.0.0 and integration_test any from sdk, version solving failed.)

This is now apparent because the minimum flutter version that we have for "the next stable after 3/3" is ">=1.27.0", however we're now in "2.0.0" (so it passes, when it shouldn't. We now really mean ">=2.1.0", but that'd break CI in stable as well).

This PR downgrades the mockito dependency so it's compatible with the integration_test package that lives in the stable version of the SDK.

Testing

• Ran tests, flutter analyze and flutter build web both in stable and master channels

Pre-launch Checklist

• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• 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.
• I listed at least one issue that this PR fixes in the description above.
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test exempt.
• 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 signed the CLA.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[ditman]

This will have to be merged in red, to fix the submit-queue.

[cyanglaz]

LGTM assuming other pre submit tasks pass

[ditman]

@cyanglaz this is a good sign: https://cirrus-ci.com/task/4659104154124288?command=main#L68

[stuartmorgan-g]

We have a bunch of other plugins using 5.0.0; maybe this should be ">=4.1.4 <6.0.0" to minimize conflicts?

[stuartmorgan-g]

(But LGTM either way)

[ditman]

We have a bunch of other plugins using 5.0.0; maybe this should be ">=4.1.4 <6.0.0" to minimize conflicts?

@stuartmorgan this is a dev_dependencies of the example package, I hope it doesn't matter (?) The problem seems to be the interaction between mockito 5 + integration_test in flutter 2.0 (it seems we don't have that combo elsewhere)

[ditman]

Merging to make tree green again