fix(connection): pg connection initialization regression (sequelize#7986

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In case the initial query contains multiple statements in the postgres connection manager, the result will be an array which is not being handled here. Since we are only interested in the rows from the very last statement, we can skip the rest.

Closes sequelize#7985

fix(querygenerator): add parentheses to queries when using ALL with L…

…IKE (sequelize#7989)

feat(dependency): Support pg version 7 (sequelize#7888)

fix(connection): pick keepAlive dialectOption (sequelize#7927)

fix(datatypes): add length to Postgres character type

feat(operators): Add $regexp operator (sequelize#7855)

Adds $regexp operator for MySQL and Postgres and its negated and case-insensitive versions.

fix(indexes): fix composite index issue (sequelize#7854)

docs(migration-guide): Mention removal of sequelize.utils from public…

… API

4.1.0

4.0.0