Add support for listing source transactions

[ob-stripe]

r? @brandur-stripe
cc @stripe/api-libraries @stan-stripe

Adds support for the /v1/sources/src_.../source_transactions endpoint.

I wrote a test, but as stripe-mock doesn't support this endpoint yet the test is skipped for the time being. Not great, but it doesn't seem like we have an easy way to stubbing requests in stripe-go tests.

[brandur-stripe]

@ob-stripe Can you double check the test code? Even if it's not run, it's still compiled, and I think the new test has a couple problems:

$ make
go test -race ./...
# github.com/stripe/stripe-go
./sourcetransaction.go:35:9: undefined: json
./sourcetransaction.go:39:3: undefined: t
./sourcetransaction.go:42:8: undefined: json
./sourcetransaction.go:46:18: undefined: t
./sourcetransaction.go:48:4: undefined: t
# github.com/stripe/stripe-go
./sourcetransaction.go:35:9: undefined: json
./sourcetransaction.go:39:3: undefined: t
./sourcetransaction.go:42:8: undefined: json
./sourcetransaction.go:46:18: undefined: t
./sourcetransaction.go:48:4: undefined: t

[brandur-stripe]

We shouldn't be mixing json and form annotations (this might have been a bad copy + paste). It also looks like you'll have to run a gofmt on this.

[brandur-stripe]

It's probably not convention elsewhere, but it might be worth failing fast here by returning an error if params.Source wasn't set. Currently I believe it'll fail with kind of a confusing couldn't find URL /sources//source_transactions 404 (or something of the sort).

[brandur-stripe]

@ob-stripe Left a couple comments above, but thanks!

[ob-stripe]

Not sure how I managed to commit a file in such a borked state, but it should be all fixed now. I also added a check for params.Source as requested.

[brandur-stripe]

Not sure how I managed to commit a file in such a borked state, but it should be all fixed now. I also added a check for params.Source as requested.

Happens to the best of us :) Thanks!

Release cut as 28.5.0.