Support dot notation for nested structs

Refactor to make package zero-dependencies

• Remove these dependencies:
  • github.com/pkg/errors
  • github.com/stretchr/testify
• Update unit tests and err messages the the module returns
• Update codecov config

Changes:

• Upgraded go version to 1.19

Fix #2: Error encountered when encoding empty slice.

Fix incorrect logic in encoding nested struct index

Thanks @agtabesh for the PR

Support custom type

Support for map

Support for interface

Fix tag parse error for embed struct

New bool format
Fix parse tag bug
Fix encode list field bug