Add codemetapy

Because it's mentioned in https://blog.datacite.org/doi-registrations-software/.

Author: katrinleinweber

content/tools.md

@@ -17,6 +17,7 @@ tool | language | codemeta version | maintainer | notes
 [CodeMeta file generator](https://gist.github.com/arfon/478b2ed49e11f984d6fb) | Ruby | 0.1.0 | [arfon](http://github.com/arfon) | (no support for current schema)
 [Bolognese](https://github.com/datacite/bolognese) | Ruby | 1.0.0 | [mfenner](https://github.com/mfenner) | primarily a tool for conversion between formats provided by DataCite, including codemeta and schema.org
 [codemetar](https://ropensci.github.io/codemetar) | R | 2.0.0 | [cboettig](https://github.com/cboettig) | Generate codemeta for R packages; + generic codemeta manipulation
+[codemetapy](https://github.com/proycon/codemetapy) | Python | 2.0.0 | [proycon](https://github.com/proycon) | Generate codemeta for Python packages