bump sqlectron-core to ^8.1.0

[MasterOdin]

Updates sqlectron-core to ^8.1.0. Its changelog:

Features

• Add cassandra authentication support
• Support MySQL caching_sha2_password authentication (default for MySQL 8)
• Use os.homedir to find user home directory (instead of hand-rolled implementation)
• Add function to database clients to get version of currently connected client
• Replace usage of deprecated createCipher / createDecipher with createCipheriv / createDecipheriv
• Add official support for MySQL 8 and Postgresql 12
• Add official support for cassandra 2.x and 3.10+
• Add official support for MariaDB 10.1+
• Add official support for Node 10 and 12 for sqlectron-core

Fixes

• Fix querying information_schema table on MySQL 8 returning results in different casing than prior versions
• Fix not being able to specify socket without a port
• Use ordinal_position to order column listing in postgresql, sqlserver, and mysql instead of relying on row ordering
• Fix truncateAllTables for sqlserver not first disabling foreign key constraints
• Fix client validator not properly rejecting invalid clients
• Fix sqlserver client breaking if using a CS collation

Dependencies

• Update mkdirp to ^0.5.2 (security)
• Move from mysql to mysql2 (better support for mysql 8)
• Update pg to ^7.18.0
• Update sqlite3 to ^4.0.6
• Move from valida to valida2
• Update babel to ^7.8.4
• Update eslint to ^4.19.1
• Update chai to ^4.2.0
• Update babel-eslint to ^10.1.0
• Update eslint-config-airbnb-base to ^11.3.2
• Update mocha to ^6.2.3
• Add nyc to get test coverage
• Update sinon to ^7.5.0

Chores

• Replace appveyor with GitHub actions
• Add automated testing for cassandra

Closes #458
Closes #444
Closes #442