Added support for MFA in AssumeRole.
Allows use of throughput kwargs with GlobalIncludeIndex - fixes #2055.
DDB queries with GSI now work with a single filter.
Fixed typo.
Merge branch 'ddb-gsi-fix' into develop

Fixes #2122.
Merge branch 'sts-assume-role-additions' into develop
Added release notes for 2.26.0.
Bumped to v2.26.0!