Build pipeline

[asogaard]

Have coverage script point to gnn_reco package rather than src/ directory for source code, as the latter only works if the package is installed as locally editable (i.e., pip install -e (...)). This change should produce actual coverage results and, as a result, an informative coverage badge.

Also fixed a warning from github-pages action, by replacing {name,email} variables with git-config-{name,email}.