Update CHANGELOG.md for v3.0.31
Update CHANGELOG.md for v3.0.31

tsotetsi/textily-web,pulilab/rapidpro,pulilab/rapidpro,tsotetsi/textily-web,pulilab/rapidpro,pulilab/rapidpro,tsotetsi/textily-web,pulilab/rapidpro,tsotetsi/textily-web,tsotetsi/textily-web