Add Maven publication to Github workflow

1. Use in-memory signing for CI workflow (#159)
2. Add publication to workflow1. Use in-memory signing for CI workflow (#159)

Codestyle fix

Bump version to 1.7.1 (#137)

Bump version to 1.7.0 (#135)

Update Java SDK (#133)

Make some refund fields optional (#132)

[ANCHOR-636] Clean up deprecation for fee_details (#129)

* clean up deprecation for fee_details

* address comments

* mark fee_details as optional for backward compatibility

* mark fee_details.asset as non-null

[WAL-1391] Auth header sig (#128)

* WAL-1391: Auth header signature

* Simplify impl

* Move query params into claims

* Remove iss

* Small fix

* Make fun public

* Replace host/path with aud

* Replace aud with web_auth_endpoint

* Add domain auth header signer

* Detekt

* bump version

* Add auth header signer

WAL-1381: Expand error message of TransactionSubmitFailedException (#127

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Improve Java compatibility (#126)