ChangeLog_highlights.rst: Add entry for 2.1.0 [skip ci]
ChangeLog_highlights.rst: Add entry for 2.1.0 [skip ci]

JimDennis/pymssql,Aloomaio/pymssql,pymssql/pymssql,Aloomaio/pymssql,bladams/pymssql,klothe/pymssql,ramiro/pymssql,bladams/pymssql,klothe/pymssql,bladams/pymssql,JimDennis/pymssql,JimDennis/pymssql,pymssql/pymssql,ramiro/pymssql,zerolugithub/pymssql,ramiro/pymssql,zerolugithub/pymssql,klothe/pymssql,zerolugithub/pymssql,Aloomaio/pymssql