add support for soroban prev 8

1.5.3

add support for soroban prev 8

soroban prev 7 & auth next support

• add soroban prev 7 support
• add soroban auth next support
• extend txrep for soroban

improve submit transaction response

• add fee meta xdr
• improve and fix tx result xdr
• improve and fix tx result meta xdr
• improve success check

Soroban support

This release adds experimental soroban support

improve webauth (sep-0010)

• add client domain signing delegate to webauth (sep-0010)
• extend and improve webauth test
• extend an improve webauth documentation

see also #51

improve null safety

This release improves the null safety functionality of the sdk. Prior to this release, null safety was supported by generated code, with most member variables and parameters of constructors and functions set as optional. We have corrected this, so that it is now precisely defined which variables are not nullable.

Other improvements of this release are:

• performance improvement
• documentation improvement and update
• improvement of test cases

update dependency packages

• update dependency packages to newest versions
• update sdk to work with the newest packages
• fix example app build

Update SEP-005 & SEP-001

• update sep-005 : add malay language
• update sep-001: improve and add new fields

txrep support for protocol 19

adds support for protocol 19 to txrep (SEP-0011)

SEP-0007 Support

adds utility features to facilitate the implementation of SEP-0007 in a Flutter Wallet