chore(deps): bump idna from 3.7 to 3.15

Bumps [idna](https://github.com/kjd/idna) from 3.7 to 3.15.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.md)
- [Commits](kjd/idna@v3.7...v3.15)

---
updated-dependencies:
- dependency-name: idna
  dependency-version: '3.15'
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -49,7 +49,7 @@ fqdn==1.5.1
     # via jsonschema
 hsds-schema-tools @ git+https://github.com/openreferral/hsds_schema_tools
     # via -r requirements.in
-idna==3.7
+idna==3.15
     # via
     #   jsonschema
     #   requests