In the bill_similarity function, find the latest version of a bill to process

[aih]

Each billnumber (e.g. 116hr133) may have more than one version. For calculating bill similarity, we are currently processing all of the bill versions, but only storing bill_similarity for one of them (arbitrarily).

Instead, for each bill, we should calculate bill_similarity for the version which has the most recent date. To do this, we can search Elasticsearch for the billnumber. That should retrieve all versions. Then we look in each version to find the date, which will be a string in the form: 2019-01-03. (I just added this to elastic_load.py, so it would require re-running the bills.

This information is also in the fdsys_billstatus.xml file for the bill, in the text_versions element (see below). However, getting the data from the elasticsearch index ensures that we have the version in the index to begin with.

<textVersions>
<item>
<type>Enrolled Bill</type>
<date/>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133enr/xml/BILLS-116hr133enr.xml
</url>
</item>
</formats>
</item>
<item>
<type>Engrossed Amendment House</type>
<date>2020-12-21T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133eah/xml/BILLS-116hr133eah.xml
</url>
</item>
</formats>
</item>
<item>
<type>Engrossed Amendment Senate</type>
<date>2020-01-15T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133eas/xml/BILLS-116hr133eas.xml
</url>
</item>
</formats>
</item>
<item>
<type>Reported to Senate</type>
<date>2019-12-17T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133rs/xml/BILLS-116hr133rs.xml
</url>
</item>
</formats>
</item>
<item>
<type>Referred in Senate</type>
<date>2019-01-11T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133rfs/xml/BILLS-116hr133rfs.xml
</url>
</item>
</formats>
</item>
<item>
<type>Engrossed in House</type>
<date>2019-01-10T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133eh/xml/BILLS-116hr133eh.xml
</url>
</item>
</formats>
</item>
<item>
<type>Introduced in House</type>
<date>2019-01-03T05:00:00Z</date>
<formats>
<item>
<url>
https://www.govinfo.gov/content/pkg/BILLS-116hr133ih/xml/BILLS-116hr133ih.xml
</url>
</item>
</formats>
</item>
</textVersions>

[aih]

Closed with #149