Update changelog.md

Merge pull request bavix#159 from bavix/develop

Postgres 12

Merge pull request bavix#153 from bavix/develop

Develop

release 4.2.2

bavix#155 fix bindTo

release 4.1.3

Merge pull request bavix#152 from bavix/develop

Develop

add issue

Merge pull request bavix#140 from bavix/develop

5.0.x - Arbitrary Precision Mathematics

Merge pull request bavix#144 from bavix/l7

add support laravel 7.x