ga: fixing revenue fallback for event value

Matches the behavior from the docs and client-side:

https://github.com/segmentio/analytics.js-integrations/blob/9243c32c8ab04c753640f27eee4e63a0abea1209/lib/google-analytics/index.js#L186
USERcycle: fix `identify` event name to match the frontend

https://github.com/segmentio/analytics.js-integrations/blob/9243c32c8ab04c753640f27eee4e63a0abea1209/lib/usercycle/index.js#L53
amplitude: adding country support

For HERE.com, when you want to specify something other than just
what the locale gives you.
Merge pull request #195 from segmentio/amplitude/add-country

amplitude: adding country support
Merge pull request #194 from segmentio/usercycle/fix-identify

USERcycle: fix `identify` event name to match the frontend
Merge pull request #193 from segmentio/ga/fix-revenue-fallback

ga: fixing revenue fallback for event value
Release 1.1.48
wip
more tests passing
ga: get mapper working
ga: add custom dimensions and metrics, closes #126
ga: send context.app
ga: add campaign info
Merge pull request #196 from segmentio/ga/add-mapper

Ga/add mapper
Release 1.1.49
ga: fix typo
Merge pull request #197 from segmentio/ga/fix-typo

ga: fix typo
Release 1.1.50
deps: depend on integration refactor
amplitude: move to new proto