fix(pypi): manual coverage sourceUrl override

Closes #2846

lib/datasource/index.js

@@ -64,6 +64,7 @@ const manualSourceUrls = {
     node: 'https://github.com/nodejs/node',
   },
   pypi: {
+    coverage: 'https://github.com/nedbat/coveragepy/', // bitbucket entry on pypi is wrong
     mkdocs: 'https://github.com/mkdocs/mkdocs',
     pillow: 'https://github.com/python-pillow/Pillow',
   },