Update coverage configuration

Use the correct package source for coverage information that is
generated and sent to Coveralls.

Co-authored-by: dav3r <[email protected]>

Author: mcdonnnj

.coveragerc

@@ -2,7 +2,7 @@
 # https://coverage.readthedocs.io/en/latest/config.html
 
 [run]
-source = src/example
+source = src/trustymail
 omit =
 branch = true