Update source/handbook/finance/procurement/index.html.md

Why is this change being made?

In an effort to streamline and remove friction, @daleb04 @bryanwise and I have agreed to eliminate the multi-bid thresholds under $100K. Contract templates have also been updated to reflect this change.

@darawarde @tbarr @zgaston

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what