Fix for ignore_submodules in older mepo clones

This patch release of mepo fixes an issue running mepo commands on older mepo clones made before v1.51.0 when ignore_submodules was added. Mea culpa.

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From CHANGELOG.md

Fixed

• Fixes to allow mepo to work on older mepo clones that don't have ignore_submodules in their state

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What's Changed

• Fixes for older mepo clones in re ignore_submodules by @mathomp4 in #261

Full Changelog: v1.51.0...v1.51.1