Add NTD 2021 funding sources

[evansiroky]

User story / feature request

As the Remix program coordinator,
I want to know if a transit agency was a 5311 recipient in 2021 NTD data,
So that we can determine if the agency is eligible for Remix.

Acceptance Criteria

Funding data is added to dim_annual_funding_sources for the year 2021.

Notes

A transit agency in California is eligible for Remix if they have received 5311 funding in the past 3 years (see announcement). The dim_annual_funding_sources currently only has data for 2022 and 2023.