Use the latest upstream richardlehane/msoleps dependency instead of a fork

[agcom]

The replace directive dependency (here) causes go install to fail:

go install code.sajari.com/docconv/v2/docd@latest

go: code.sajari.com/docconv/v2/docd@latest (in code.sajari.com/docconv/v2@v2.0.0-pre.4):
	The go.mod file for the module providing named packages contains one or
	more replace directives. It must not contain directives that would cause
	it to be interpreted differently than if it were the main module.

Further more, the referenced commit in the replace directive dependency does not belong to any branch (sajari/msoleps@d0092b82abea), probably because the branch was deleted after a successful PR.

As the temporary fork fix is merged into upstream (see here), revert to using the latest version of that.